Gwinn Firearms Company
Captain Mack Gwinn was a Special Forces officer who decided to start a firearm company after his retirement from the U.S. Army. He had extensive experience with the Stoner 63A rifle throughout the Vietnam War and sought to produce a long-stroke gas piston rifle that had similar controls to the AR-15.
In 1972, he started the Gwinn Firearms Company and introduced a rifle and pistol, both based on the same concept. While simple and crude, the firearms were popular enough to gain the attention of several folks in the firearm industry.
Bushmaster Steps In
In 1973, a company known as Quality Parts purchased the Gwinn Firearms Company, taking ownership of both designs. At the same time, Quality Parts restructured and rebranded as Bushmaster Firearms. While Bushmaster was not the mastermind behind the invention, the designs were designated the Bushmaster Assault Rifle and the Bushmaster Arm Pistol.
These two firearms would establish Bushmaster as a major player in the U.S. firearm market. In 2020, Bushmaster was part of the Remington Bankruptcy filings before Franklin Armory bought and brought back the company in 2021.
The Purpose of the Arm Pistol
The Bushmaster Arm Pistol is designed to be pressed up against the bicep and fired from the hip. The concept originated with an Air Force survival weapon proposal that was unsuccessful.
In the early 1960s, the Air Force was looking for a new Aircrew Survival Weapon. Remington entered the search with an experimental bullpup bolt-action weapon chambered in .221 Fireball, the XP100.
Then came Colt's take on the requirement, a very compact sub-gun in the same .221 Fireball caliber. Dubbed the Individual Multi-purpose Weapon and type classified as the GUU-4/P, the 1.5-pound gun with a 13-inch total length was capable of firing out to 100 meters effectively. The IMP-221 had an offset forward grip to allow the rear of the gun to rest on the forearm of the user. Just five were made, although the military concedes, “These weapons exceeded the expectations expected of them.”
In the 1970s, the design lent itself well to domestic production, as it featured an 11.5-inch barrel but was designed to be fired with one hand. This kept the firearm free of NFA restrictions as a Short Barrel Rifle.
Design Features
The Bushmaster Arm Pistol is a combination of two popular firearms, the AR-15 and the AK-47. The AK-style long-stroke gas piston is known for reliability. While there is a stronger recoil impulse, the system runs cleaner than direct impingement since the gas is not directed into the chamber and on the bolt.
The pistol is chambered in 5.56x45mm NATO and feeds from STANAG-style AR magazines. It also features the rotating bolt design invented by Melvin Johnson for the 1941 Johnson rifle and later used for the AR-15.
The most unique aspect of the design is the rotating pistol grip. The main receiver is designed to be canted to the left or right, making it easier to tuck the end of the firearm into your bicep. In fact, there is a safety feature that prevents the trigger from being pulled if the rifle is not completely canted to one side or locked in the middle.
The Arm Pistol also features a crude set of sights, as you can also hold the pistol with both hands and fire it like a traditional handgun. The sights also rotate to the left or right to accommodate the orientation of the receiver.
On the Range
