Bushmaster Arm Pistol
Gwinn Firearms Company · Pistol · Discontinued · 1972
Also known as: Gwinn Bushmaster Arm Pistol, Bushmaster Pistol
Overview
The Bushmaster Arm Pistol is an American compact bullpup pistol chambered in 5.56x45mm NATO. Developed from the experimental USAF IMP-221 (GUU-4/P) survival weapon of the early 1970s, it combines an AK-style long-stroke gas piston and rotating bolt with a bullpup layout that places the 30-round STANAG magazine behind the pistol grip. The grip pivots around the barrel axis up to about 40 degrees for left- or right-handed off-hand firing, making it one of the most unusual personal defense weapons of its era.
Specifications
| Weight (empty) | 1930 g (68.1 oz) |
| Overall Length | 510 mm (20.08") |
| Barrel Length | 290 mm (11.42") |
| Action Type | Gas Operated |
| Firing Mechanism | Hammer Fired |
| Trigger Type | Single Action |
| Magazine Capacity | 30 rounds |
| Magazine Type | Detachable Box |
| Effective Range | 100 m (109 yd) |
| Barrel Rifling | Right Hand |
| Frame Material | Aluminum Alloy |
| Barrel Material | Steel |
| Finish | Anodized |
Calibers
- 5.56x45mm NATO · primary · 5.56mm NATO — also known as 5.56 NATO, 5.56x45mm, .223 Remington (chamber compatible)
Features
- Firing modes: Semi Automatic
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety
- Features: Bullpup Layout, Long Stroke Gas Piston, Rotating Bolt, Pivoting Pistol Grip, Stanag Magazine, Iron Sights
Service history
Operators
- United States Air Force
Production
Production years: 1972-1990
Produced in limited quantities by Gwinn Firearms Company and later Bushmaster Firearms International
Origin
Country of origin: United States
Designer: Mack Gwinn Jr.
Discontinued: 1990
Notes
Civilian semi-automatic versions were produced; the design originated as a select-fire aircrew survival weapon. Manufactured by Gwinn Firearms of Bangor, Maine and later by Bushmaster Firearms International.
Background
The Arm Pistol traces its lineage to the Individual Multi-Purpose Weapon (IMP-221), designed by Dale Davis of the USAF Armament Laboratory and built by Colt as a compact survival arm for downed aircrew. Mack Gwinn Jr., a former Special Forces soldier, refined the concept into the Bushmaster Arm Pistol, whose swivelling grip allowed it to be fired one-handed from either side.