A revival of the M3 .45-caliber submachine gun, more commonly known as the “Grease Gun,” is taking place at Bazooka Brothers Manufacturing. Unsatisfied with the original’s departure from the battlefield in the 1950s, the company is producing an updated version in the form of a .45-caliber AR-15. Instead of completely redesigning either weapon, Bazooka Brothers’ offering, designated the BAZ45 Carbine, combines the best components of each into a single modern and familiar platform built not only to fire the Grease Gun’s ammunition, but also to accept its unique 30-round magazine.
To achieve functionality with .45 ACP, the BAZ45 combines a Bazooka Brothers-designed lower receiver manufactured by REO Engineering and an RMW Extreme direct impingement upper receiver, both assembled into a complete weapon at the Bazooka Brothers shop in Russiaville, Indiana. Though unique in its design, the BAZ45 follows the familiar setup of an M4 and other AR-15 platforms and is available in both semi- and full-auto models. Its lower receiver is CNC-machined from a solid billet of 6061 stainless steel that has a Type III hardcoat-anodized finish. It includes DPMS parts, which are interchangeable with all Mil-Spec lower kits, and requires no specialty pieces.
Several significant modifications were made in the lower’s design, only one of which was necessary to alter the caliber to .45 ACP, the rest included simply to improve overall function. The most obvious modification is to the magazine well. Here, the lower is cut to the size and shape of the Grease Gun or stick magazine, wire EDM’d, flared to assistant docking, and then anodized. To improve functioning and ease of installation, a threaded bolt is used in the bolt stop rather than a pin.
The rear takedown pin detent hole has also been threaded and includes a set-screw to allow its stock to be removed without the worry of losing the spring or detent during field maintenance. To strengthen the lower, its winter-style triggerguard is forged with the receiver and additional material is added to the area surrounding the buffer tube. For style and branding, the company’s logo, a plastic green army man holding a bazooka like a childhood toy, is etched on the magazine well. A Leapers six-position collapsible stock rounds out the lower half of the weapon. Molded from impact-resistant polymer, it features a push-button release on its base that allows the user to pull the stock rearward to the desired length.
Unlike the handful of other .45 ACP AR-15 upper receivers in production, all of which rely on blowback systems, the RMW Extreme installed on a BAZ45 is direct impingement. Made of stainless steel with a 1-in-8-inch twist, it is compatible with standard AR-15 parts.
Its only deviation is a bolt face modified to accept the .45 ACP and a proprietary gas block. By using a direct impingement system, the BAZ45 avoids failures common to blowback systems that allow excess carbon to build up and degrade the weapon’s function. The advantages of this design are extensive and include reduced felt recoil, reduced muzzle rise, a cleaner chamber and parts commonality.