Developed during World War II, the M3 machine gun was a variant of the M2 intended for aircraft use, maintaining the general bulk and the same hard-hitting 50 BMG chambering, but boosting the rate of fire to 1,200 rounds per minute. The M3 was airplane armament into the jet age, and is still seen on some active prop aircraft, helicopters, and ground emplacements like the "Up-Gun" variant of the Avenger Air Defense System deployed to Afghanistan. According to an included narrative, Wayne Pump of Fort Wayne, Indiana made this machine gun as a "proof of concept" for the Saginaw Steering Division of General Motors, for whom Wayne was a parts supplier, to show they were equipped to manufacture a complete machine gun. Saginaw didn't bite, as they were getting out of the machine gun business at that point. The letter mentions that the gun later ended up in the collection of Dennis Tippman of Tippman Arms Company (noted manufacturer of miniature Gatling guns and Browning-pattern machine guns), who confirmed the Wayne/Saginaw story to the writer; a copy of a 1980s vintage Form 4 confirms Tippman as the transferor of this machine gun. This particular M3 has been outfitted with a heavy water cooling jacket, which would be typical for use in the air defense role from a fixed ground position or land vehicle mount. A fixed blade front sight is set in a protective cover on the water jacket, with a flip up ladder rear sight on the receiver behind the feed cover. The right sideplate bears the Wayne Pump markings, with a left side feed arrangement, smooth plastic grips on the charging handle and spade grips, dual thumb triggers, and a rotating manual safety. Included with the M3 is an extra barrel, a folding field mount (note: pintle and T&E mechanism not included), and a standing pintle mount, and a metal ammo can suitable for mounting to the standing pintle.

Excellent, with 97% plus of the parkerized finish, showing some light rubbing and handling marks overall. Some light scuffs are present on the grips, which are otherwise in fine order. The field mounts are untested, and the safety needs some minor adjustment; otherwise, the gun appears in fine order. NOTE: This weapon is a National Firearms Act (NFA), fully transferable Class 3, which is registered with the Bureau of Alcohol, Tobacco, Firearms and Explosives, (BATFE) under the provisions of 18 U.S.C. Chapter 44 and 27 CFR part 478.