BACKGROUND: There are two common variations the Mk I used on the Ross Model 1905 rifle, this rifle was issued to the Canadian Militia Regiments prior to WW1 and to the Canadian Battalions when they took their training here in Canadian, they never were used overseas during WW1. The Mk II bayonets went with the Ross Model 1910 rifle, this is the rifle that went overseas with the First Division and had all the controversy about the rifles jamming in the mud. The Ross Mk I and Mk II bayonets when manufactured were identical except for the cross guard, both their blades had the knife profile. In October of 1915, the blades on the Mk II's were grounded to a point to increase their penetration ability, only a very few of the Mk II bayonets missed this conversion (Thanks to Dennis K for the background)