Just picked this up, a very nice condition Mk 1 Ross Bayonet. 20,000 of these were purchased for stateside training in the US before troops headed overseas. Rifles and Bayonets that were used by US forces had the shell and flame and "U.S" acceptance marks. Although the Ross rifle was not well designed for trench warfare and had a poor performance record, it did fairly well in training environments and was used as a sniper rifle.