I’d like to share with you some technology and design ideas about firearm, archery gear and crossbow modifications and adaptations.
This information is for anyone with compromised or a total loss of hand strength, missing digits or, in my case, the absence of an entire hand—knowledge that will enable them to safely handle a long gun, shotgun or compound bow, traditional bow or crossbow.
I’ve experimented with firearm and bow modifications since 1971, when an auto accident resulted in the crushing of my lower left forearm, requiring an amputation below my elbow. I wear a custom left-arm prosthesis equipped to couple with multiple devices that quickly attach and detach at the wrist.
A simple military strap can provide additional control over the fore-arm and stock of a rifle, carbine, shotgun or crossbow. The shooter needs to be equipped with a prosthesis, or have a partial or complete arm that can engage the strap. However, the control over the firearm or crossbow is only marginal using a strap of this type. Beginning in the 1970s and in the last few years, I fabricated pistol-grip-style adapters that mechanically and structurally attached to the guns I was using. This worked well and provided the safe control that was required to shoot a 12-gauge shotgun or high power rifle. These modifications were permanent, however, and clouded the firearm’s value, preventing it from being easily resold. Additionally, the modification also compromised “normal use” of the firearm by another person. However, these adaptions provided safe and confident control over the firearm when it was swung above the shoulder level, as required in trap, skeet, wingshooting and hunting sports.
Shooting a bow—whether it be a compound or traditional style—is a different challenge. If you need to hold the bow with your left-arm prosthesis, assuming that you are right-handed and right-eye dominant, then a prosthetic device option called the is available. It adapts to virtually all arm prostheses and positions and supports the bow without inducing torque into the riser, while drawing and releasing the arrow. If, however, you need to draw the bow string with a right-handed arm prosthesis, then a prosthetic string release accessory is available to solve that challenge. If you are left handed, then just use these same devices on the opposite side, since they operate universally either right or left-sided. Modern crossbows, in many cases come equipped with Picatinny rail systems for accessories. I mounted a Fab Defense, quick-disconnect pistol grip to my Ten Point Siege 410 Crossbow with ease.
Since my accident, my career has been devoted to upper extremity prosthetic component design and manufacturing. During the first USA-involved wars in the Middle East, therapists and prosthetic medical professionals from Walter Reed Army Hospital (originally located in Washington, D.C., now in Rockville, Maryland) reached out to my company (A. Fillauer TRS, formerly TRS Prosthetics, Inc.) with a design request for a specialized prosthetic adapter for shooting. The device needed to adapt to “M style-platform” military guns, as well as other commercial-type hunting rifles and shotguns. No gun modifications were allowed. Walter Reed was implementing shooting sports into their rehabilitation program for soldiers returning from combat, who had lost or severely damaged hands, or who were otherwise physically injured and compromised. A major objective during rehabilitation was to enable the soldier or veteran, using an arm prosthesis, to control the firearm safely by supporting, pulling and holding it securely into their shoulder for stability. This project resulted in the design of the Lamprey Gun Turret prosthetic device. The Lamprey employed a flexible, proprietary polyurethane-molded “yoke” that easily grappled securely to virtually any gun forearm, without interfering with the gun’s function, the sight plane or other firearm accessories. The gun would remain secure in the Lamprey during firing but could be removed (snapped on and off) the gun easily after a little practice. The Lamprey also has a high-strength, lockable, stainless-steel ball-and-socket system that provides a wide range of angular adjustments at its base. The device has been widely used and accepted as a functional and safe solution for handling firearms. The downside to this solution is that it is so specific in function, thus, the shooter typically must change out their prosthetic adapter for other two-handed activities.
In 2020, I began experimenting with rifle and shotgun barrel adapters that incorporated Picatinny rail systems for mounting gun accessories like laser sights, flashlights, etc. I purchased a Benelli 828U 20-gauge over-under shotgun primarily for my daughter, who was expressing an interest in developing her shooting skills and upland bird hunting. I wanted to shoot this gun myself, as well, so I used the Lamprey system to get the feel of the gun. However, my personal preference in shooting is using my regular prosthetic device, a GRIP 5 Voluntary-Closing Prehensor (GRIP V/C GRIP Prehensor manufactured by Fillauer TRS) and modifying the firearm. Since this was a valuable gun, I did not want to damage the stock or modify it in any way that would compromise its value.
I experimented with several designs and finally settled on the Lion’s Gear Universal Barrel Mount (five-slots) for 18 mm to 25 mm barrels, Picatinny rail single-barrel adapter. This adapter system provided a secure barrel mounting support, from which I was able to attach a Picatinny rail-compatible, easily removeable pistol grip. These particular Picatinny rail barrel adapters, machined from aluminum, are a solid solution to create a stable platform for these pistol grip accessories. The firearm remains uncompromised with no damage to the gun.
My research also proved fruitful in discovering a similar adapter for my early 1940s, 12-gauge Ithaca field-grade, double-barrel shotgun. I had replaced the entire stock around 2010 and did not want to mar the new walnut or alter the gun permanently. The Picatinny rail barrel adapter captured the side-by-side barrels securely and worked perfectly. The challenge with these adapters was not finding and attaching a pistol grip to the Picatinny rail system. There are many pistol grips and styles available that adapt to barrel-mounted Picatinny rail systems. The issue was that the barrel adapter placed the pistol grip too far forward on the gun, making it awkward and uncomfortable to sight and shoot.
The solution, which was custom for each of these two firearms, required fabricating an extension that would bring the pistol grip rearward, “proximally,” to a more natural stock supporting position. Using some 6061 aircraft aluminum stock (sourced through McMaster-Carr), I fabricated two extension systems to solve the problem (Photos 10). The extension for the Benelli allowed me to fabricate a straight 3/16-inch thick extension using 1½-inch wide material. The Ithaca, however, required a double bend in the aluminum to get the extension to maintain a close alignment to the tapered stock for positioning the pistol grip properly, yet still providing some needed clearance to the stock. A good hobby torch, vice and hammer allowed me to get the correct angles in the extension for the Ithaca. I also modified the Fab Defense Reg. Rubberized foregrip—quick-detach pistol grip—for both firearms by cutting them down in length, since they were longer than I desired. I also employed a special Picatinny accessory, “Picatinny to Arca-Swiss Adapter” (*see more information at the bottom of this article) to capture and support the extensions where they came off below the barrel(s). Some drilling and tapping was needed to get all these components to fit securely together and still look reasonably clean.
Everything was readily detachable. I also carefully coated the inside of the aluminum barrel adapters with a thin layer of liquid brushable Flex Seal. This protected the surface of the barrels and provide a high friction element that would prevent the adapter from shifting on the barrel when the gun was fired. Finally, I added a circular cushion-pad to the top of each aluminum extension (above the pistol grip) to protect the stock in case the aluminum extension flexed under load.
I have access to a small shop, drill press, metal band saw, belt sanders and other tools, so I was able to get this fabrication completed myself. If you are mechanically inclined and have access to these types of machines and tools, then you can get these same modifications completed yourself. If not, share these ideas and designs with a local gunsmith and I’m sure that they can replicate these types of adaptations for your firearm.
So, hopefully some of these design ideas, prosthetic adaptors and accessory Picatinny rail barrel components will enable you to start or rekindle a love of safe shooting and hunting. These designs will improve your control over your firearm and provide you with the ability to more safely and competently access shooting sports and hunting.
*The following accessories were used to construct the pistol grip modifications on both the Benelli and Ithaca shotguns.
- Lion’s Gear Universal Barrel Mount, five slots for 18 mm-25 mm single barrels, bridge mount BMR1825
- Gotical Tactical Double-Barrel Shotgun mount with five-slot 20/21 Picatinny rail
- Picatinny to Arca-Swiss adapter, Tough Tactical tools
- TRYBE Defense Magnnite M-Lok Picatinny rail section, five slots
- Fab Defense Reg. Rubberized fore-grip
About the author: Robert (Bob) Radocy was born in Fairfield County, Connecticut, in the late 1940s. He grew up with his dad, an uncle and an older cousin, all who enjoyed the outdoors, fishing and hunting. He cut his teeth pheasant hunting with these elders when he was 11. His cousin taught him to tie flies and fly fish when he was nine. When Bob was 22 and a senior in college, he was involved in a severe auto wreck. He survived that accident, but the result was the loss of his left hand below the elbow. That incident initiated his lifelong pursuit of improved prosthetic designs. His educational background is in engineering, biological science and recreational therapy. In 1979, he started TRS Prosthetics in Boulder, Colorado, which became a worldwide pioneer in developing high performance prosthetic components for persons with an upper extremity absence. He is responsible for dozens of designs and multiple patents. He became seriously interested in archery in 1976 and bowhunting has been his primary hunting technique since then, although he also enjoys certain types of hunting with firearms. Bob sold his business in 2019, and continued to work full-time until January 2023, when he semi-retired. He continues to be involved in prosthetic product research and development at Fillauer TRS, still in Boulder, Colorado. Email Bob Radocy at [email protected].
All photos courtesy of Bob Radocy and Fillauer TRS.
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