The grouping includes 20 of these rare .22 caliber adapters for the Model 1903 Hoffer-Thompson Gallery Practice rifle. The practice rifles were identical to the 30 caliber Model 1903 rifles except were fitted with a .22 caliber barrel. .22 caliber rounds are put into the adapters then the rifle is loaded with the stripper clip. Also included is a tool marked "GD OD USA".