In August 1913, the British War Office wrote to Sir Charles Ross requesting a sample automatic rifle for trials in the UK. Ross was able to submit a prototype on May 1914, which was tested at Enfield – but only fired 308 rounds before the test ended, suggesting that something important probably broke. The gun was a very strange looking contraption, whose Ross MkIII lineage is visible only in the bolt and front of the receiver forging. A long stroke gas pistol was added, and the action flipped upside-down. A large 25-round magazine was fitted, along with a thumbhole style stock that looks very similar to the grip of a Lewis gun. In addition to one example tested at Enfield in .303 caliber, one other model was send to the US for testing, chambered for .30-06. That is the gun we are looking at today, which came to the Canadian War Museum from the collection stored at Fort Knox in the 197-s and 80s.
Thanks to the Canadian War Museum for providing me access to film this extremely unusual Ross for you!