Years before he co-founded Sturm, Ruger & Co., Bill Ruger worked for Auto-Ordnance. When the Army’s Ordnance Department was seeking a replacement for the M1919A4 light machine gun, he designed and submitted a prototype. Unfortunately for Ruger, it failed the endurance test as did the other submissions. Ultimately, the Army went with an updated version of the Browning design.
Ian McCollum goes on to add this about the prototype which now is part of the Cody Firearms Museum’s collection.
As it turns out – and as Ruger would later write – it could be quite hard to create a ground-up new design to beat John Browning’s work in just 4 or 5 months (shocking!). When Ruger’s gun was tested, it was found to have a few good aspects, but was generally unreliable and failed to complete the scheduled 10,000-round endurance test. All of the other guns in that trial failed for various reasons, though, and a second trial was scheduled, giving the manufacturers time to improve their designs. Ruger and Auto-Ordnance were unable to substantially correct the problems with the gun, however, and it did as badly in the second trial as it had in the first. Ultimately, a separate procurement process by the Infantry Department would result in the M1919A6 Browning, which was adopted for the role of light machine gun.
This experience would serve Ruger well, as he would go on to do quite a lot more work with Auto-Ordnance before forming his own tremendously successful company.