SINGLE ARM SHOTGUN (SAS) KIT
MOSSBERG 500 & REMINGTON 11-87
A Baccalaureate thesis submitted to the
School of Dynamic Systems
College of Engineering and Applied Science
University of Cincinnati
in partial fulfillment of the
requirements for the degree of
Bachelor of Science
in Mechanical Engineering Technology
by
Ryan Brodbeck
Ryan Slattery
April 2013
Thesis Advisor: Amir Salehpour
TABLE OF CONTENTS
TABLE OF CONTENTS .......................................................................................................... II
LIST OF FIGURES ................................................................................................................ III
LIST OF TABLES .................................................................................................................. III
INTRODUCTION .................................................................................................................... 1
RESEARCH.............................................................................................................................. 2
CUSTOMER SURVEY ............................................................................................................ 5
CUSTOMER REQUIREMENTS ............................................................................................. 6
PRODUCT OBJECTIVES ........................................................................................................................................8
ANALYSIS OF USER DEMANDS FOR DESIGN QUALITY ........................................... 10
CONCEPT GENERATION.................................................................................................... 11
FORE GRIP REDESIGN ....................................................................................................................................... 11
ACTION REDESIGN............................................................................................................................................. 12
FINAL DESIGN ..................................................................................................................... 13
FORE GRIP FINAL DESIGN ................................................................................................................................ 13
TRIGGER MECHANISM ....................................................................................................................................... 14
ACTION FINAL DESIGN ..................................................................................................................................... 15
CONNECTOR PLATE DESIGN.............................................................................................................................. 16
STOCK DESIGN .................................................................................................................................................. 17
FELT RECOIL REDUCTION .................................................................................................................................. 18
FINAL ASSEMBLY .............................................................................................................................................. 19
PROJECT MANAGEMENT .................................................................................................. 20
SCHEDULE ........................................................................................................................................................ 20
BUDGET: PROPOSED.......................................................................................................................................... 21
WORKS CITED ..................................................................................................................... 22
APPENDIX A – RESEARCH ................................................................................................ 24
APPENDIX B- CUSTOMER SURVEY WITH RESULTS .................................................. 36
APPENDIX C- QFD ............................................................................................................... 37
APPENDIX D-PRODUCT OBJECTIVES ............................................................................ 38
APPENDIX E- SCHEDULE .................................................................................................. 40
APPENDIX F- DIMENSIONAL DRAWINGS ..................................................................... 42
APPENDIX G- BUDGET ...................................................................................................... 58
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LIST OF FIGURES
Figure 1 Side by side double barrel shotgun with a custom grip on the stock ......................... 2
Figure 2 Custom built fore-grip support ................................................................................... 2
Figure 3 Bi-lateral amputee utilizing a harness for firearm support ......................................... 2
Figure 4 SPAS 12 shotgun stock using a hook under forearm for support............................... 3
Figure 5 Taurus’s “The Judge” ................................................................................................. 3
Figure 6 Shotgun with "Bull pup" modification ....................................................................... 3
Figure 7 Custom Over/Under shotgun bull pup modification .................................................. 3
Figure 8 Hierarchical List of Engineering Features from Customer Requirements 1 of 2 ....... 6
Figure 9- Hierarchical List of Engineering Features from Customer Requirements 2 of 2 ..... 7
Figure 10 Some of the complex mechanical linkage of .......................................................... 11
Figure 11 Original trigger connection idea ............................................................................. 11
Figure 12 Flexible connector bar and moveable guide ramp .................................................. 11
Figure 13 Action Spring Design Alternative 1 ....................................................................... 12
Figure 14 Action Spring Design Alternative 2 ....................................................................... 12
Figure 15 Fore Grip Final Design Iteration ............................................................................ 13
Figure 16 Deflection of front trigger connector bar................................................................ 13
Figure 17 Thoery of Operation of Trigger Assembly ............................................................. 14
Figure 18 Top Section View of Action Spring Relocation ..................................................... 15
Figure 19 Rear Isometric View of Spring Connector, Guide, and Connector Cable.............. 15
Figure 20 Spring Connector Assembly Exploded View ......................................................... 16
Figure 21 Shoulder Plate and Quick Connect Attachment ..................................................... 16
Figure 22 RH Shell Isometric View........................................................................................ 17
Figure 23 LH Shell Isometric View ........................................................................................ 17
Figure 24 Muzzle Brake for Remington 11-87 ....................................................................... 18
Figure 25 Final Assembly Isometric View 1 .......................................................................... 19
Figure 26 Final Assembly Isometric View 2 .......................................................................... 19
LIST OF TABLES
Table 1 Customer Survey Results ............................................................................................. 5
Table 2 Engineering Characteristics with Relative Importance ............................................. 10
Table 3 Schedule ..................................................................................................................... 20
Table 4 Budget ........................................................................................................................ 21
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
INTRODUCTION
Throughout the world there are hundreds of millions of people that use firearms for
various reasons. There are hunters, competition and recreational shooters as well military and
law enforcement personnel. In all cases, there are instances where a long barreled firearm is
used. In this case study, shotguns are looked at specifically.
The shotgun weighs roughly eight and one half to ten pounds. Its large size requires the
use of two hands in order to operate it effectively and safely. Complications arise when
someone who needs to use a shotgun only has the use of one arm or using only one arm
would be more ideal
In the case of someone with the use of only one arm, the reasons are varied. They can
include work related accidents, medical conditions, combat, and others. In most cases, the
shooter is no longer able to shoot as effectively or safely. Depending on the severity of the
injury, there may not be a suitable prosthetic available to provide the shooter with the
dexterity needed to maintain the same level of performance in post-accident shooting.
In the case of someone being in a situation in which the use of one arm is more ideal,
this would include military and law enforcement personnel that engage in close quarters
combat and room clearing operations. In these situations, the shooter must provide cover to a
sector of fire as part of their operational responsibilities. The shooter must also secure
personnel encountered during these operations so as to reduce injuries to non-combatants.
When the shooter removes their hand from the fore grip to secure someone or open a door,
the barrel of their firearm drops, preventing them from providing cover in their sector of fire.
In both cases, it is apparent that the shooters effectiveness with the firearm is reduced
and safety becomes a serious issue when only one hand is available to operate a firearm that
requires the use of two hands. Given how common this issue is, it can be seen that an ideal
solution could be a shotgun fitted with a multiplatform modular kit that can be operated more
effectively and safely with one hand than one hand shooting of a shotgun that requires the
use of two hands.
The proposal is to design and build a prototype kit that will adapt to two commonly
used shotguns, the Mossberg 500 (pump-action) and the Remington 11-87 (Semi-automatic).
This kit will give a one-armed shooter a way to handle the gun safely and more easily
without any modification that could decrease the performance of the gun. The main focus of
the project will be the buttstock, trigger system, and recoil system for the Remington 11-87,
and the buttstock, trigger system, and fore grip for the Mossberg 500. Two design teams will
work interdependently, with one focusing on the Mossberg 500 and the other on the
Remington 11-87. In this manner, the details of the individual platforms (pump action or
semi auto) can have more attention paid to them while facilitating the integration of universal
parts.
Before one can design something new, one needs to research to see what current
solutions exist for the problem you are researching. The next section will cover the research
done into what is currently available to consumers in terms of both custom made and mass
production aftermarket parts.
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Single Arm Shotgun (SAS) Kit
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RESEARCH
As previously mentioned, one must know what is currently available before the decision
can be made that there is a need for a new solution to be pursued. The research conducted
looked into what is available both custom made and mass produced.
Initial research into firearm manufacturers produced variations of shotguns that were
very similar to the shotgun pictured in Figure 1 (1). This one has a
custom stock which makes the shotgun more ergonomic for the user.
However, there is still the issue of weight which fatigues the user as
well as the forces from the recoil of the firearm when shooting. This
can cause serious injuries to the shooter’s wrist and increase the
chance of an accidental discharge. Because of the impracticality of
this design, there has been various aftermarket options made available
to the general public. It has also led to some custom solutions made
for persons with prosthetics.
Some of the custom made solutions for persons with prosthetics
are for those whose prosthetic is of the older metal bar grabber style.
Figure 1 Side by
This style of prosthetic provides the user the ability to open and close
side double
the grippers so as to firmly grab objects. The front fore grip of the
barrel shotgun
shotgun has a wood handle attached to it that has been custom carved
with a custom
to fit the shape of the users grabber. This method can be quite costly
grip on the stock
with the designers charging upwards of $1000 for a single fore grip
adaptor. Another custom solution was the use of a “mechanical arm”.
This arm attached to the shooter’s waist and to the fore grip of the
shotgun as shown in figure 2 (1). However, it is clear in the picture that
this solution does require the use of a second arm as a stabilizer when
firing the weapon. This would not be a feasible option for anyone that
does not have use of both arms. Also considered is the mobility issues
that would arise from a device like this. Because of safety issues, this
would be best suited for static shooting and if the angle of the shotgun
Figure 2 Custom
is not adjustable then it is only good for shooting upwards from a
built fore-grip
ground position as done in clay pigeon shooting and bird hunting.
support
Shooters could not hunt from a tree stand as that requires
downward shooting or move much in this set up.
In Figure 3 is a gentleman that is a bi-lateral amputee,
utilizing a harness to support the back end of the firearm against
his body. This is a very effective means of immobilizing the
buttstock for shooting while allowing enough range of motion to
maintain some maneuverability. It appears as the shooter is able
to shoot utilizing no further firearm modifications. This would be
a good base to build upon for the single arm shotgun kit.
Figure 3 Bi-lateral
amputee utilizing a
harness for firearm
support
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Single Arm Shotgun (SAS) Kit
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There are aftermarket parts available that modify
the butt stock in such a manner that shooters could
shoot one handed a bit easier. The kit pictured in
Figure 3 (1) has a hook at the end of the metal framed
butt stock that loops under the shooter’s forearm. This Figure 4 SPAS 12 shotgun stock
helps the shooter stabilize when shooting but all the
using a hook under forearm for
forces from recoil are going directly into the shooter’s
support
wrist. This could cause serious damage to the
shooter’s wrist as shotguns have recoil forces of 20 to 50 foot pounds. Also, a shorter barrel
must be installed to help reduce the weight of the barrel out in front of the shooter’s hand.
While the installation of a new barrel is easy and fast it can be expensive.
There has been a new type of revolver made available in recent years that has been very
popular among self-defense enthusiasts. It is called “The Judge”,
made by Taurus, shown in Figure 4 (2). It is a .45 caliber revolver
that can shoot both .45 ball rounds and .410 shotgun shells.
Manufacturers have also begun production of task specific .410
shells for self-defense that shoot small disks instead of bird shot
like the standard .410 shotgun shell. While this revolver offers
Figure 5 Taurus’s “The
great mobility, the range is limited as compared to a shotgun
Judge”
with a 24 or 28 inch barrel. There is still the issue of
tremendous forces going directly into the wrist, so this would not be ideal for repetitive
shooting like in trap shooting and competition shooting.
There are some designs that use what is called a “bull pup” modification. This is where
the trigger assembly is shifted forward and the bolt
assembly and chamber are moved closer to the body as
shown in figure 5 (3). This redistributes the weight very
well but without the aid of a second hand, the shooter
would fatigue faster trying to hold the shotgun against their
Figure 6 Shotgun with "Bull
body during repeated shooting. This is an ideal platform to
pup" modification
begin with for a one handed model given the mobility,
effectiveness, and safety of the two handed version.
Figure 7 shows a custom bull pup mod for an
over/under shotgun. This application utilizes a
vertical forward grip for ergonomics and direct
linkage to connect to the original trigger. This
instance was a one off design specifically for this
firearm and would not work for a pump shotgun or
Figure 7 Custom Over/Under shotgun
semi-automatic.
bull pup modification
An interview was conducted with Andy Kling.
Andy is mid-left arm amputee. He is an active sportsman who shoots shotguns more
frequently than any other type of firearm. The interview was conducted via phone on
November 7, 2012. He pointed out his two largest problems with shooting were muzzle jump
(due to the force of the projectile leaving the barrel) and the weight distribution of the gun.
Since he has lost a lot of muscle in his arm due to the amputation, the gun is difficult for him
to hold up. (4)
Another interview was conducted with a user on the forum ohiosportsman.com known as
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Single Arm Shotgun (SAS) Kit
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‘spitfirekills’ on September 9, 2012. He is a mid-right arm amputee and an active sportsman.
He used a Mossberg 500 to hunt after fully recovering from the amputation. Since he was not
able to pump the gun one handed, he was only able to load one shell at a time (defeating the
purpose of the pump shotgun). (5)
Through reasearch it is found that there is need to pursue a new design for a one handed
shotgun. While there are already some solutions available on the market, they all lack
features that consumers are looking for and most notably they are not designed with one
handed operation in mind. The next section will look into the wants and needs of the
customer via customer surveys.
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
CUSTOMER SURVEY
In composing the customer survey, brainstorming, comparison, and analysis pointed to
18 items of interest to include. After finalizing the layout of the survey, it was posted it to the
project website rr-outdoors.com and the link was forwarded to persons with a known interest
in firearms through means of social media. In all, 75+ surveys were collected through the
web site which provided the data that will be utilized as the design process moves forward.
The survey and raw data collected can be found in Appendix B. Table 1 shows the results of
all that data as it will be
Table 1 Customer Survey Results
applied it to the design
process later on. The data
shows that to the customers,
safety is the number one
concern when purchasing a
firearm or aftermarket part.
Next is Durability and Ease
of Operation. The decision
was made to add a
designer’s multiplier to Ease
of Installation as this kit is
being designed for persons
that can only use one arm.
Therefore, easy installation
should have a slightly higher
importance than where the
customer had placed it.
Everything else seemed to
be reasonable and the group
from which the data was
collected are a
knowledgeable group whose
firearm experience range
from recreational and clay
pigeon shooting to current
and former military and law enforcement. This indicates that the data collected will lead to
the best design possible.
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
CUSTOMER REQUIREMENTS
The interviews proved to be helpful when developing a list of requirements from the customer’s wants and needs. These
requirements can be formed into engineering features. Below is a hierarchical list (Fig. 7 & 8) showing the relationship between the
engineering features and the customer requirements.
Safety
Does not
decrease the
safety of the
gun
Limited
internal firearm
modifications
Durability
Won't break
when dropped
Gun can be
cleaned
without
damaging the
kit
Ease of
Operation
Easy to load
East to reload
Ease of
Installation
No specialty
tools to install
Range of
Motion
Does not limit
the movement
of the shoter
Balance
Well balanced
making it easier
to hold up
As few of steps
as possible
Maneuverability
Easy to control
the weapon in
different
shooting
situations
Easy to aim
Wont break
while shooting
Figure 8 Hierarchical List of Engineering Features from Customer Requirements 1 of 2
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Single Arm Shotgun (SAS) Kit
Ergonomics
Comfortable
to hold and
fire
Weather
Resistance
Should not be
affected by
being
outdoors
Light
Weight
Will not
add
weight
Ryan Brodbeck, Ryan Slattery
Reduced
Recoil
Reduce
recoil felt
by shooter
Cost
As inexpensive
as possible
Ease of
Cleaning
No
complicated
steps to clean
Not time
consuming to
clean
Appearance
Not bulky
and
awkward
Stock
Material
Should be a
lightweight
material
Resistant to
chemicals
and
lubricants
normally
associated
with
firearms
Accessory
Rails
Rails to add
accessories
like a scope
Color (i.e.
Camouflage)
Different
colors
Available
Figure 9- Hierarchical List of Engineering Features from Customer Requirements 2 of 2
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
PRODUCT OBJECTIVES
A list of objectives for the kit was developed to meet the customer requirements. The
engineering features are listed with their relative weight and the objective to fulfill each of
the features.
1. Safety
7.1%
a. Must conform to Federal Firearms Laws
b. No factory safety modifications
c. Limited internal firearm modifications
d. Addition of trigger safety to Mod kit
e. Design factor consistent with loading conditions in expected use
2. Durability
6.7%
a. Impact/shock resistant testing
b. Material resistant to lubricants, solvents, cleaners, and other chemicals
involved in firearms
c. Design that meets or exceeds the expected loading conditions
d. Firearm spec sheets warranty information
3. Ease of Operation
6.5%
a. Adding stability to hold the gun still while loading
b. One-handed cycling of the action of the gun after a shot or reload
c. One-handed aiming and firing
d. Does not interfere or hinder any operations of the firearm
4. Ease of Installation
6.3%
a. Basic tool
b. Reduced number of parts (DFA)
c. Less than 6 steps
5. Range of Motion
6.2%
a. Fore grip placement position to be consistent with human factors of adult
b. Gun Stock range of motion will match that of the user
6. Balance
6.2%
a. Reduce distance from body to the existing center of mass by 30%
7. Maneuverability
6.2%
a. Shooter should be able to safely and properly perform basic shoot and move
maneuvers consistent with hunting, clay pigeon shooting, and home defense
8. Ergonomics
5.7%
a. Handle and trigger assemblies should conform so as to allow the shooters
hand, wrist, and arm to line up in a manner consistent with proper shooting
techniques
b. End of butt stock mount should conform to the shoulder pocket of the shooter
in a manner consistent with proper shooting techniques
9. Weather Resistance
5.7%
a. Material should be able to handle the same environmental hazards as factory
firearm
10. Light Weight
5.4%
a. Maintain factory weight
11. Reduced Recoil
5.3%
a. Recoil Calculations
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
b. Force distribution calculations
12. Cost
5.3%
a. Production cost below $350
13. Ease of Cleaning
5.0%
a. Remove need for lubrication of kit parts
b. Choose material for mild detergent and water cleaning
c. Should add no more than 15 minutes to total firearm cleaning time
14. Appearance
4.5%
a. Smooth or textured surfaces
b. Flat or curved surfaces
c. Should it be “high speed, low drag”?
15. Stock Material
4.5%
a. Should be a lightweight material to maintain factory weight
b. Resistant to chemicals and lubricants normally associated with firearms
16. Accessory Rails
4.2%
a. Rails should be designed consistent with the picatinny rail system to fit other
accessories currently on the market
17. Color (i.e. Camouflage)
3.7%
a. Variety of colors available for injection molding
b. Dipping processes currently exist to add custom computer designs
Following the product objectives as listed above will ensure the best design possible. The
input from the surveys comes from good sources with credible backgrounds. With their
input, the weights of each objective will guide the design process in the best direction
possible.
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
ANALYSIS OF USER DEMANDS FOR DESIGN QUALITY
After an analysis of the customer input, engineering characteristics that would best
satisfy these requirements had to be identified. In order for an importance to be placed on
each of these engineering characteristics, analysis and comparisons of the relationships
between the customer requirements and the engineering characteristics had to be performed.
The relationship is rated on a scale of 1: Weak, 3: Moderate, 9: Strong. If there is no
relationship, the cell is left blank. Calculations are performed to determine a weighted value
for each characteristic. These weighted values indicate the importance of the characteristics
so as to determine which takes precedence should an issue arise between two of the
characteristics. Shown in Table 2, the most important characteristics are the material, weight,
and shape which were found to be strongly related. The material used will directly affect the
weight of the overall product and the shape will dictate how much material will be used.
Following these characteristics is size, impact forces, and weight distribution, which were
found to be related as well. The size of the final product will directly affect the weight,
impact forces will drive the selection of the material and shape, and the weight distribution
will help reduce user fatigue by helping compensate for the weight of the product. These top
six engineering characteristics will be the most important as the design process develops.
Table 2 Engineering Characteristics with Relative Importance
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
CONCEPT GENERATION
FORE GRIP REDESIGN
Through the use of a “bull pup” style modification, the fore grip design will have to
mechanically connect the new trigger to the existing factory trigger. Also, the design will
need to account for the pumping action associated with reloading the Mossberg 500 pump
action shotgun. There were
several variations of front end
designs that were considered
with two of the three having
more cons than pros. Fore Grip
Design Iteration I utilized a
complex network of mechanical Figure 10 Some of the complex mechanical linkage of
Fore Grip Design Iteration I
linkage within the trigger grip
housing to provide the mechanical movement necessary to push the original trigger. Some of
these small parts are shown in Figure 10. This design proved to be far too complex for the
small amount of space provided within the handle. The overall number of moving parts that
pivot at different locations through use of fixed or moving pins makes this design difficult to
assemble and thus undesirable. However, there was one usable idea from Fore Grip Design
Iteration I.
What was kept from that design was the idea of how to connect to the original trigger, as
shown in Figure 11. We liked the idea of a single push bar
coming from the front trigger as shown in the bottom left
corner. This would reduce the number of objects needing
to be disconnected from or bypassed in the trigger housing
during the pumping motion. The idea of supporting the
original trigger cross bar on both sides would give great
strength and stability during the trigger pull, however it
Figure 11 Original trigger
could be difficult to assemble with the trigger cross bar
connection idea
needing to be aligned on both sides. If the load can be
handled by a single supported member, it would be in the final design iteration.
Fore Grip Design Iteration II utilized a set of links that were able to pivot in only the
vertical direction. These sections would be
completely supported during the trigger pull as
shown in Figure 12. This design used a thin bar of
flexible metal that would help provide rigidity when a
compressive load was applied during the trigger pull.
After the trigger pull, the user would pull down on a
slide lever on the grip which would move an internal
ramp guide down to disconnect the trigger from the
flexible connector bar. Ideally the flexible section of
Figure 12 Flexible connector bar and
connector bar would glide up and over the ramp and
moveable guide ramp
out the front of the grip body. However, this motion is unpredictable; this lack of reliability
led to Fore Grip Design Iteration III.
Fore Grip Design Iteration III is the evolution of ideas from both Fore Grip Design
Iterations I and II which resulted in the Final Fore Grip Design Iteration.
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Single Arm Shotgun (SAS) Kit
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ACTION REDESIGN
The buttstock needed to be shortened significantly to reduce the length of pull (distance
between the buttstock and the trigger) of the shotgun to a comfortable length since the trigger
is being move to the foregrip
of the gun. The biggest
problem with shortening the
buttstock is the action spring
of the bolt. This spring is
compressed by the bolt from
the forces of the expanding
gasses propelling the bullet
foreword. Once the bolt moves
to the rear, the empty shell
Figure 13 Action Spring Design Alternative 1
casing is ejected and the
compressed spring pushes the bolt foreword. The first design concept changed the spring to
two tension springs which were relocated more towards the forend. The design was compact,
but called for custom springs and it would be difficult to assemble inside the buttstock.
The second design removed the need for tension springs and used compression springs. The
bolt connecter would have been expensive to machine and somewhat difficult to assemble as
well.
Figure 14 Action Spring Design Alternative 2
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
FINAL DESIGN
FORE GRIP FINAL DESIGN
The Fore Grip Final Design Iteration uses the straight connector bar idea from Fore Grip
Design Iteration I, only modifying it so that the bar itself is offset from center. This
distributes the compressive load evenly,
through a straight path, up to the post
that contacts the factory trigger during
trigger pull, as shown in Figure 15. This
allows the design of the stock to be such
that a majority of the long slender bar
will be almost fully encased and
Figure 15 Fore Grip Final Design Iteration
supported. The offset also helps to
facilitate the disconnecting and
bypassing of trigger linkage during the pumping motion of the pump action shotgun. The
grip also houses the connector bars for the bolt slide block on the pump action shotgun
facilitating the connection required to move the bolt to the rear and pull it back forward
during reloading operations. The bolt slide block connector bars would not be used when this
kit is applied to the Remington 1187 semi automatic shotgun. Also, the grip would double as
a spacer holding the barrel on as it does not need to move.
Within the grip, the ideology of the flexible material within the connector rods was
reversed. The idea of a flexible bar through pivoting links was done away with and replaced
with using a materials own properties to our advantage. ABS
plastic is a lightweight material that can be easily manufactured.
It also has flexibility characteristics that are useful in this design
iteration. The design calls for a bar connected to the new trigger
that will contact the bar that connects to the factory trigger. This
connection is made by deflecting the bar connected to the new
trigger, as shown in Figure 16. This is accomplished when the
shooter pushes in on the red button protruding from the outside
of the grip. The shooter holds the button in during the trigger pull
and then releases the button to allow the new trigger connector
bar to deflect back to its original position. When the hew trigger
connector bar is in its natural unbent state, the factory trigger
connector bar can bypass the new trigger assembly during the
pump motion.
Overall, this new bull pup design is made up of seven parts
of which only five are used in the semi automatic shotgun
Figure 16 Deflection of
application. This is a relatively simple design that takes up
minimal space, is lightweight due to the material to be used, and front trigger connector bar
is strong enough to reliably function properly due to its being encased in grip and stock.
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Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
TRIGGER MECHANISM
The operation of the trigger mechanism and the manner in which it connects to the
factory trigger is the key to the bull pup mod applied in this kit. The theory in this system is
forcing a deflection into a material to align it with another material, thus making a solid
connection to the factory trigger. Figure 17 shows what can also be seen in the Pump Handle
Design Theory video.
Figure 17 Thoery of Operation of Trigger Assembly
In order for the shooter to fire, the red safety button must be engaged. Pressing the red
safety button deflects the orange front trigger connector bar 0.13 inches, in line with the
yellow rear trigger connector bar. At this point the shooter can pull the green trigger, moving
the orange and yellow trigger connector bars in unison. This action engages the factory
trigger, firing a round. If the shooter chooses to reload, the red safety button and green trigger
need to be released. This allows the orange front trigger connector bar to return to its original
position and allows the yellow rear trigger connector bar to bypass the internal mechanics fo
the pump handle during the pumping action. The operation remains the same for use on the
semi automatic Remington 1187 with the exception that the shooter does not need to perform
the pumping action to chamber the next round. Since the shooter doesn’t need to pump in this
application, the shooter doesn’t need to release the red safety button when performing follow
up shots.
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Single Arm Shotgun (SAS) Kit
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ACTION FINAL DESIGN
The current design incorporates the existing compression spring in the gun itself. The spring
is relocated to the non-ejection port side of the receiver. It is connected to the bolt using a
coated steel cable. The motion of the Action can be seen in the Spring Assembly video.
Figure 18 Top Section View of Action Spring Relocation
The cable connects to the spring connect which is the link between the bolt and spring.
Figure 19 Rear Isometric View of Spring Connector, Guide, and Connector Cable
The spring connector is made from a high strength, aircraft grade aluminum alloy to keep the
weight as minimal as possible. The connector was also made from two pieces to add
adjustability. It also decreases cost and manufacturing difficulty.
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Single Arm Shotgun (SAS) Kit
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Figure 20 Spring Connector Assembly Exploded View
The spring connector is housed in the spring connector guide, which is being printed on a abs
plastic rapid prototype machine. This is being made from abs plastic to keep the weight
down. Since the guide is inserted into a wood cavity it is fully supported b the surrounding
stock. This is shown in yellow in Figure 12. In order to install the spring connector guide the
action spring tube must be cut down to 1.125” long.
CONNECTOR PLATE DESIGN
The buttstock needs to be supported at an affixed point, since the gun is being supported at
the foregrip by the shooting hand.
A bracket is used to attach and
detach the gun from a vest worn
by the shooter.
This bracket has been enlarged to
increase the distribution area of
the energy from the gun to the
shooters body. This was taken
into account with the buttstock
and all of its components. The
locking mechanism is made out of
the same aircraft grade aluminum.
The shoulder plate is made from a
high density abs plastic. The
shoulder plate is connected a high
range of motion rod end. This was
much more economical than
fabricating a custom joint to fit
the shoulder plate. The rod end is
Figure 21 Shoulder Plate and Quick Connect Attachment inserted the buttstock of the gun
using a quick release as shown in the Shoulder Plate Animation video This way the shooter
will not have any problems attaching the gun to the shoulder plate. The latch for the adapter
16
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
is made of the same high quality aluminum as the spring connector. A stainless steel spring
with a spring rate of 18 lbs/inch was selected to hold the latch shut in the adapter. Human
factors references show the average adult pinch (similar motion to holding the stock and
pushing the release) is 18lbs (6). The adapter itself is to be made out of carbon steel such as
1024 so the internal threads can withstand the shock loading from the firearm.
The rod end used to connect the shoulder plate is a purchased component. The smallest
available in the “super swivel” rod end was a 3/8 shank. This is more than enough to
withstand any of the forces of the gun. A larger size would only add more weight to the
system. The rod end is connected to the shoulder plate using a shoulder bolt to ensure a close
fit. The bold is held in place with a nylon insert lock nut so it will not vibrate lose while
operating the firearm.
STOCK DESIGN
The stock design is universal between the Mossberg 500 and Remington 11-87 models. It has
been designed to house all of the necessary components for the SAS Kit. The prototype is
being built out of walnut, which is to be cut with a CNC router. For production the stock
would be injection molded. This will reduce the need for some of the parts in the kit like the
spring connector guide. To make the help with machining, the tock was split into two halves.
The each of the halves is mounted on the gun and then fastened together. Due to the
complexity of the stock, the stock is to be cut from the model. The some of the geometries in
the stock are too complicated to place on a 2 dimensional drawing.
Figure 22 RH Shell Isometric View
Figure 23 LH Shell Isometric View
17
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
FELT RECOIL REDUCTION
The energy from the gun is considered to be the felt recoil. A 3.5 inch magnum load in an 8
lb shotgun results in 63 ft lbs of energy, which is the largest standard load (7).
The felt recoil is reduced a number of ways. The simplest is by
adding padding to the back of the buttstock. The cushion
absorbs some of the guns recoil energy reducing the felt recoil.
A more complex (if it is not yet designed) way is redirecting
the expanding gasses as they exit the barrel. This is
accomplished using a muzzle brake which attaches to the end
of the barrel. This allows for optimal acceleration through the
entire length of the barrel. It also minimizes the effect of the
gas redirection on the projectile. The muzzle brake will usually
direct the gases out the sides of the brake at an angle toward
opposite the direction of the projectile. The muzzle brake seen
in Figure _ is designed and manufactured by Grizzly
Gunworks. The company claims a 40% reduction in felt recoil.
Figure 24 Muzzle Brake
This would reduce the felt recoil to about 38 ft lbs.
for Remington 11-87
18
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
FINAL ASSEMBLY
Below are some pictures of the complete assembly.
Figure 25 Final Assembly Isometric View 1
Figure 26 Final Assembly Isometric View 2
19
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
PROJECT MANAGEMENT
SCHEDULE
Below (Table 3) is the schedule for the three phases of the project; design, prototype, and
presentation of the SAS kit.
Table 3 Schedule
TASKS
Proof of Design to advisor
Concept sketches to advisor
Selection of Final Design Solution
Impact Calculations
Recoil Force Calculations
3D Model - (Main Body)
3D Model - (Fore Grip Assembly)
3D Model - (Trigger Assembly)
3D Model - (Recoil Assembly)
3D Model - (Anchor Assembly)
3D Model - (Anchor Plate)
3D Model - (Final Assembly)
Finite Element Analysis
Part Refinement
Standard Part Selection
Bill of Materials
Manufacturing Process Selection
Material Selection
Oral Report to Faculty
Written Report to Advisor
Prototype Parts
Assemble Prototype
Manuverability Testing
Range of Motion Comparison
Function Testing
Recoil Testing
Demonstration to Advisor
Post Testing Analysis and Adjustment
Oral Report to Faculty
Final Report
Date
Oct 14 - 20
Oct 21 - 27
Oct 28 - Nov 3
Nov 4 - 8
Nov 8 - 30
Dec 1 - 15
Jan 13 - 19
Jan 20 - Feb 28
Mar 1 - 14
Mar 15 - 28
Apr 1 - 11
Apr 12 - 18
20
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
BUDGET: PROPOSED
The proposed budget is for the group. It breaks down the combined cost of the building and
testing of the kit. It specifies two prototypes since the kit will be for one pump and one semiautomatic shotgun. The individual cost of building and testing each prototype is $1260.
Materials, Components or Labor
Table 4 Budget
Forecasted Amount Actual Amount
Testing Materials
(2 Prototypes)
$300
$125
Material Costs
(2 Prototypes)
$1000
$250
Prototype Costs
(2 Prototypes)
$600
$650
Standard Parts
(2 Prototypes)
$200
$150
MISC @ 20%
$420
$0
_______________________________________________________________________
Total
$2520
$1175
21
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
WORKS CITED
1. Shotgunworld.com. [Online] September 6, 2012. [Cited: September 8, 2012.]
http://www.shotgunworld.com/bbs/viewtopic.php?f=2&t=306216.
2. Taurus. Taurususa.com. [Online] 2012. [Cited: Sept 4, 2012.]
http://www.taurususa.com/productdetails.cfm?id=663&category=Revolver&toggle=tr&breadcrumbseries=41.
3. Popenker, Max R. Modern Firearms Shotguns. world.guns.ru. [Online] 2010. [Cited:
Sept 5, 2012.] http://world.guns.ru/shotgun/usa/high-standard-10a-10b-e.html.
4. Kling, Andy. Phone Interview, 11 7, 2012.
5. OhioSportsman.com. [Online] September 8, 2012. [Cited: Septermber 10, 2012.]
http://www.ohiosportsman.com/forum/showthread.php?p=601735#post601735.
6. Karwowski, Waldemar. International Encyclopedia of Ergonomics and Human Factors,
Volume 1. s.l. : CRC Press, 2006. p. 370 TABLE 2.
7. Bourjaily, Philip. Bourjaily: I Hate the 3 1/2-inch Turkey Load. Field & Stream. [Online]
March 2009. http://www.fieldandstream.com/blogs/ammunition/2009/03/bourjaily-i-hate-312-inch-turkey-load.
8. Benner, John. Instructor at Tactical Defense Institute. September 2012.
9. TheHighRoad.org. [Online] September 4, 2012. [Cited: September 8, 2012.]
http://www.thehighroad.org/showthread.php?t=675765.
10. Crouch, Alferd H. One-Arm Shotugn and Flashlight. 3488488 U.S., May 18, 1967.
11. Archery Talk. [Online] September 2012. http://www.archerytalk.com.
12. Deer & Deer Hunting. [Online] September 8, 2012. [Cited: September 10, 2012.]
http://www.deeranddeerhunting.com/forum/viewtopic.php?f=5&t=32571.
13. Lipsey's Firearm Finder. lipseys.com. [Online] Lipsey's, 2008. [Cited: August 31, 2012.]
http://www.lipseys.com/itemdetail.aspx?itemno=MB85110&mfg=Mossberg&family=930+A
utoloader+Series.
14. Mossberg. mossberg.com. [Online] Mossberg & Sons, 2012. [Cited: August 31, 2012.]
http://www.mossberg.com/product/shotguns-autoloading-930-all-purpose/85110.
15. SodaHead. sodahead.com. [Online] SodaHead, 2012. [Cited: September 2, 2012.]
http://www.sodahead.com/living/youre-alone-in-your-house-its-late-at-night-you-suddenlyrealize-three-burglars-have-broken-into/question1168585/?link=ibaf&q=mossberg+930&imgurl=http://www.gunreports.com/media/newspics
/Mossberg930.jpg.
16. Mossberg Owners. mossbergowners.com. [Online] Mossberg Owners Forum, 2010.
[Cited: September 2, 2012.]
http://www.mossbergowners.com/viewtopic.php?f=22&t=3495&start=25.
17. Arms List. armslist.com. [Online] armslist, 2012. [Cited: September 2, 2012.]
http://www.armslist.com/posts/153536/indianiapolis-indiana-shotguns-for-sale-trade-mossberg-930-spx.
18. Dan Hanovich Photography. danhonovich.com. [Online] Dan Hanovich, 2012. [Cited:
September 5, 2012.] http://www.danhonovich.com/img/s3/v26/p50261029-4.jpg.
19. CombatStocks.com. combatstocks.com. [Online] CombatStocks.com, 2012. [Cited:
September 5, 2012.]
http://www.combatstocks.com/Choate_Mossberg_500_600_590_Top_folder.cfm.
20. Harris Tactical. harristacticalonline.com. [Online] Harris Tactical, 2012. [Cited:
September 4, 2012.] http://harristacticalonline.com/Shotgun-Telescoping-and-Replacement-
22
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Stock-Systems_c86.htm.
21. Calguns. calguns.net. [Online] Calguns, 2012. [Cited: September 2, 2012.]
http://www.calguns.net/calgunforum/showthread.php?t=444564.
22. AR15 Armory. ar15armory.com. [Online] AR!% Armory, 2012. [Cited: September 5,
2012.] http://www.ar15armory.com/forums/lofiversion/index.php?t72643.html.
23. Elite Tactical Advantage. elitetacticaladvantage.com. [Online] Elite Tactical Advantage,
2012. [Cited: September 2, 2012.]
http://www.elitetacticaladvantage.com/xcart/product.php?productid=4.
24. XR Underground. xr-underground.com. [Online] XR Underground, 2012. [Cited:
September 4, 2012.] http://www.xr-underground.com/forum/showthread.php?t=33776.
25. Radocy, Bob. Atlas of Limb Prosthetics: Surgical, Prosthetic, and Rehabilitation
Principles. American Academy of Orthopedic Surgeons. II. Rosemont : American Academy
of Orthopedic Surgeons, 2002, 12C, p. Chapter 12C.
23
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX A – RESEARCH
Interview with industry expert: John Benner of Tactical Defense Institute (TDI) 2174
Bethany Ridge West Union, OH 45693 Date: Have not interviewed yet. Setting up a meeting
on 12/10/12
He has 37+ years in the weapons training and law enforcement. TDI has been featured on
local news stations for specializing in weapons training for amputees. (8)
Forum Reply from shotgunworld.com (9/8/12): We received 8 replies in this thread so far
and will be using this forum until our list of features is complete. In this thread, users have
commented on stories of an arm amputee in their club, and they also replied with pictures of
current and past alternative products.
A side by side double barrel shotgun with a custom grip on the stock and
some other small modifications. This was made by a famous London Gun Builder,
Robert Churchill
Appendix A-24
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
http://www.shotgun
world.com/bbs/view
topic.php?f=2&t=30
6216
A custom built fore-grip support for an arm amputee
http://www.shotgun
world.com/bbs/view
topic.php?f=2&t=30
6216
Alternate view of same custom support shown above
This support system is quite cumbersome. It also adds extra weight to the already heavy
shotgun. The good thing about this system is the recoil is absorbed into the shoulder rather
than the wrist or forearm.
Appendix A-25
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
http://www.oandplibrary.org/alp/
chap12-03.asp
Modified shotgun for Hemiplegic.
http://www.oandplibrary.org/alp/
chap12-03.asp
Shotgun adaptations for a bi-lateral amputee
Appendix A-26
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Forum Reply from thehighroad.org(9/8/12) (9): We received 19 replies in this thread so far
and will be using this forum until our list of features is complete. In this thread, users have
commented on more stories of an arm amputees in their shooting club or friend that were arm
amputees, and they also replied with pictures of other current and past alternative products.
Figure 4 shows a over-under double barrel shotgun no modifications being reloaded by an
arm amputee.
http://www.shotgun
world.com/bbs/view
topic.php?f=2&t=30
6216
This man is using an over under shotgun where each round of ammunition
has to be loaded one at a time and the gun only holds two rounds. He has to hold his
gun awkwardly between his legs to reload.
Appendix A-27
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
This is very unbalanced allowing the wrist and forearm to receive the shock of the large
amount of recoil from a 12ga shotgun.
http://www.thehighroa
d.org/showthread.php?
t=675765
A SPAS 12 shotgun stock using a hook under forearm for support
http://www.thehighroa
d.org/showthread.php?
t=675765
-Alternate view of SPAS 12 shotgun stock
Appendix A-28
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
http://world.guns.r
u/shotgun/usa/high
-standard-10a-10be.html
High Standard HS-10A (10)
This was not built specifically for a one-armed person, but a forum member pointed out how
the HS-10A was balanced and how some of the design concepts could be useful for holding it
with only one arm
http://www.thehighroa
d.org/showthread.php?
t=675765
A small shotgun (.410 ga) pistol. (9)
This could not be used for a 12ga or 20ga because the recoil would cause too much shock
and fatigue to the wrists. Also the accuracy is much less than a long barrel shotgun.
Appendix A-29
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Forum Reply from archerytalk.com (9/8/12): We received 6 replies in this thread so far and
will be using this forum until our list of features is complete. In this thread, users have
commented on the fact barrel length will be a big factor in balancing the gun with only one
arm. They also replied with pictures a link to a current alternative product “The Judge”
made by Taurus. (11)
http://www.taurususa.com/p
roductdetails.cfm?id=663&categor
y=Revolver&toggle=tr&bre
adcrumbseries=41
Taurus’s “The Judge” is similar to the pistol on the previous page but can hold more than one
round. It also has the same problems as explained above in
Forum Reply from deerandeerhunting.com: We received 4 replies in this thread so far and
will be using this forum until our list of features is complete. In this thread, a user gave us
the contact information for the Host of Kentucky Afield, Tim Farmer. Time Farmer is a well
known outdoorsman who does everything with only one good hand. We are awaiting reply
from Tim Farmer. (12)
Forum Reply from ohiosportsman.com: We received 6 replies in this thread so far and will
be using this forum until our list of features is complete. In this thread, a user from Greene
County, Ohio was amputated between the wrist and elbow just 4 years ago. He explained the
difficulties of shooting an “off the shelf” shotgun for an entire year before receiving his
prosthetic. He also offered any information he could give us. We are also awaiting reply on
a meeting time. (5)
Appendix A-30
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
The Mossberg 930 Autoloader is a standard 12 gauge shotgun that is affordable, dependable,
and near the top of all lists for hunting shotguns. Low price and high popularity among
recreational shooters mixed with a large number of aftermarket modification parts makes the
Mossberg 930 ideal for this project.
Mossberg 930 Sales Information (13)
http://www.lipseys.com/i
temdetail.aspx?itemno=
MB85110&mfg=Mossbe
rg&family=930+Autoloa
der+Series
Mossberg 930 Sales Information (14)
http://www.mossberg.co
m/product/shotgunsautoloading-930-allpurpose/85110
Appendix A-31
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
The Mossberg 930 Autoloader is a typical semi auto shotgun that is easily found in use and
for sale across the country. It is used in a wide range of firearm activities from hunting and
competition shooting to recreational target shooting and home defense. It is such a popular
model that Mossberg currently offers 6 variations to suit the hunter and recreational shooter,
6 variations for home defense and tactical situations and 2 signature series variations by Jerry
Miculek and Patrick Flanigan, the fastest pistol and shotgun shooters in the world
respectively. (15)
http://www.sodahead.com/liv
ing/youre-alone-in-yourhouse-its-late-at-night-yousuddenly-realize-threeburglars-have-brokeninto/question1168585/?link=ibaf&q=moss
Mossberg 930 Autoloaderberg+930&imgurl=http://ww
w.gunreports.com/media/ne
wspics/Mossberg930.jpg
The design of a shotgun gives it a bit of weight at the portion of the shotgun furthest away
from the body. This creates a leverage issue and impacts the maneuverability of all long
barrel firearms when acquiring a target. Manufacturers have developed front hand grips that
are more ergonomic, which provides control over the end of the long barrel firearm; however
these front hand grips are only useful to two armed persons. (16)
http://www.mossbergowners
.com/viewtopic.php?f=22&t
=3495&start=25
Front hand grip with flashlight
http://www.armslist.com/p
osts/153536/indianiapolisindiana-shotguns-for-saletrade--mossberg-930-spx
(link works but sale
deactivated by seller)
Generic front hand grip (17)
Appendix A-32
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
An easy to change part of any firearm is the butt stock. There is a huge selection of different
styled aftermarket butt stocks that one can purchase for their firearm. Depending on the style
selected, one can add to the versatility of their firearm. The butt stock selected can help
improve control, speed up target acquisition, improve mobility, or increase the flexibility of
the firearm. These are the features the customer wants available to them and so our design
should incorporate as many as feasible without detracting from the more important design
considerations of the project.
http://www.danhonovich.
com/img/s3/v26/p502610
29-4.jpg
Various butt stock styles (18)
http://www.combatstocks
.com/Choate_Mossberg_
500_600_590_Top_folde
r.cfm
Fold away butt stock (19)
http://harristacticalonline.
com/ShotgunTelescoping-andReplacement-StockSystems_c86.htm
Butt stock with adjustable cheek pad (20)
http://www.calguns.net/c
algunforum/showthread.p
hp?t=444564
Factory butt stock exploded diagram (21)
In the cycle of operations, the unloading of a spent shell and reloading of a new shell is done
either manually or automatically after a certain point. The speed at which a new shell can be
reloaded greatly impacts your ability to perform follow up shots or acquire new targets. On
an autoloader shotgun, the shells are unloaded and loaded automatically after the first shell
has been loaded. The ability to load the first shell and unload any unspent shells at the end of
a shooting session are key to the safe handling and operation of a firearm. This will be an
Appendix A-33
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
area to focus on during the designing of the system.
http://www.ar15armory.c
om/forums/lofiversion/in
dex.php?t72643.html
Standard ejection port with charging handle (22)
http://www.elitetacticala
dvantage.com/xcart/prod
uct.php?productid=4
Alternate view of standard ejection port with charging handle (23)
As with any aftermarket part available to the average consumer, these aftermarket parts all
offer something the original factory parts did not. Features like the adjustable butt stock,
extended heavy duty rail system for attaching more high speed/low drag gadgets and gizmos
like the mini M203 grenade launcher, and extra shell storage right on the shotgun itself.
While nice as they may be, some bells and whistles will have to be left out of the design
process. These extra features add unnecessary weight and do not always contribute to the
main function of the project.
http://www.xrunderground.com/foru
m/showthread.php?t=3
3776
Aftermarket Rail System (24)
http://www.xrunderground.com/foru
m/showthread.php?t=3
3776
Aftermarket Rail System with mini M203 (24)
Appendix A-34
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
http://www.ar15armory.
com/forums/lofiversion/i
ndex.php?t72643.html
Aftermarket ammunition holder
Appendix A-35
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX B- CUSTOMER SURVEY WITH RESULTS
SHOTGUN KIT FOR ONE-HANDED OPERATION
CUSTOMER SURVEY
We are University of Cincinnati engineering technology students conducting research to
design a kit for people who have lost the use of one of their arms. It will be for use with
either a pump or semiautomatic (a.k.a. autoloader) shotgun.
Please circle the level of importance of each feature you would consider for this kit.
1 = Low importance
5 = High importance
Average
Safety
1(1)
2(0)
3(1)
4(4)
5(12) N/A
4.4
Durability
1(1)
2(0)
3(3)
4(5)
5(9)
N/A
4.2
Low Cost
1(0)
2(5)
3(8)
4(1)
5(4)
N/A
3.2
Ease of Installation
1(2)
2(3)
3(5)
4(6)
5(2)
N/A
3.2
Lightweight
1(2)
2(3)
3(5)
4(3)
5(5)
N/A
3.3
Range of Motion
1(2)
2(0)
3(0)
4(8)
5(8)
N/A
4.1
Reduced Recoil
1(2)
2(4)
3(3)
4(3)
5(6)
N/A
3.4
Ease of Cleaning
1(3)
2(3)
3(6)
4(4)
5(2)
N/A
2.9
Ease of Operation
1(1)
2(1)
3(1)
4(6)
5(9)
N/A
4.2
Appearance
1(2)
2(2)
3(9)
4(3)
5(2)
N/A
3.1
Weather Resistance
1(1)
2(2)
3(4)
4(5)
5(6)
N/A
3.7
Ergonomics
1(1)
2(0)
3(6)
4(6)
5(5)
N/A
3.8
Accessory Rails
1(4)
2(2)
3(8)
4(2)
5(2)
N/A
2.8
Stock Material
1(3)
2(4)
3(5)
4(3)
5(0)
N/A
2.8
Color (i.e. Camouflage) 1(7)
2(4)
3(4)
4(2)
5(1)
N/A
2.2
Balance
1(1)
2(0)
3(3)
4(8)
5(6)
N/A
4.0
Impact Resistance
1(1)
2(2)
3(3)
4(9)
5(3)
N/A
3.6
Maneuverability
1(2)
2(0)
3(1)
4(10) 5(5)
N/A
3.9
Which shotgun bore size do you most often use while hunting/shooting?
12 ga(12)
20 ga(3)
.410 ga(0) 16 ga(0) Other_________(3)
What is the price range you would expect to pay for this kit?
$100-$200(4) $200-$300(6) $300-$400(4) $400-$500(3) $500-$600(0) $600+(1)
THANK YOU FOR YOUR TIME
Appendix B-36
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX C- QFD
Appendix C-37
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX D-PRODUCT OBJECTIVES
Below is a list of objectives to be completed based on the research in Appendix A. This list of
objectives is weighted based on surveys given to customers. Each objective has been split into a more
specific task in order to specify exactly what will be completed in each objective.
1. Safety
7.1%
a. Must conform to Federal Firearms Laws
b. No factory safety modifications
c. Limited internal firearm modifications
d. Addition of trigger safety to Mod kit
e. Design factor consistent with loading conditions in expected use
2. Durability
6.7%
a. Impact/shock resistant testing
b. Weather resistant material
c. Material resistant to lubricants, solvents, cleaners, and other chemicals
involved in firearms
d. Design that meets or exceeds the expected loading conditions
e. Firearm spec sheets warranty information
3. Ease of Operation
6.5%
a. Adding stability to hold the gun still while loading
b. One-handed cycling of the action of the gun after a shot or reload
c. One-handed aiming and firing
d. Does not interfere or hinder any operations of the firearm
4. Ease of Installation
6.3%
a. Basic tool
b. Reduced number of parts (DFA)
c. Less than 6 steps
5. Range of Motion
6.2%
a. Fore grip placement position to be consistent with human factors of adult
b. Gun Stock range of motion will match that of the user
6. Balance
6.2%
a. Reduce distance from body to the existing center of mass by 30%
7. Maneuverability
6.2%
a. Shooter should be able to safely and properly perform basic shoot and move
maneuvers consistent with hunting, clay pigeon shooting, and home defense
8. Ergonomics
5.7%
a. Handle and trigger assemblies should conform so as to allow the shooters
hand, wrist, and arm to line up in a manner consistent with proper shooting
techniques
b. End of butt stock mount should conform to the shoulder pocket of the shooter
in a manner consistent with proper shooting techniques
9. Weather Resistance
5.7%
a. Material should be able to handle the same environmental hazards as factory
firearm
Appendix D-38
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
10. Light Weight
5.4%
a. Maintain factory weight
11. Reduced Recoil
5.3%
a. Recoil Calculations
b. Force distribution calculations
12. Cost
5.3%
a. Production cost below $350
13. Ease of Cleaning
5.0%
a. Remove need for lubrication of kit parts
b. Choose material for mild detergent and water cleaning
c. Should add no more than 15 minutes to total firearm cleaning time
14. Appearance
4.5%
a. Smooth or textured surfaces
b. Flat or curved surfaces
c. Should it be “high speed, low drag”?
15. Stock Material
4.5%
a. Should be a lightweight material to maintain factory weight
b. Resistant to chemicals and lubricants normally associated with firearms
16. Accessory Rails
4.2%
a. Rails should be designed consistent with the picatinny rail system to fit other
accessories currently on the market
17. Color (i.e. Camouflage)
3.7%
a. Variety of colors available for injection molding
b. Dipping processes currently exist to add custom computer designs
Appendix D-39
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX E- SCHEDULE
Appendix E-40
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix E-41
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX F- DIMENSIONAL DRAWINGS
Appendix F-42
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-43
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-44
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-45
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-46
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-47
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-48
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-49
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-50
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-51
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-52
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-53
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-54
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-55
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-56
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
Appendix F-57
Single Arm Shotgun (SAS) Kit
Ryan Brodbeck, Ryan Slattery
APPENDIX G- BUDGET
Materials, Components or Labor
Forecasted Amount Actual Amount
Testing Materials
(2 Prototypes)
$300
$125
Material Costs
(2 Prototypes)
$1000
$250
Prototype Costs
(2 Prototypes)
$600
$650
Standard Parts
(2 Prototypes)
$200
$150
MISC @ 20%
$420
$0
_______________________________________________________________________
Total
$2520
$1175
Appendix G-58