I have one of these also.  Every course for Volunteer, Militia and Regular Army Instructors at the School of Musketry culminated in a Teams Match between groups formed from amongst the members of that Course.  This means that there were a number of these cups awarded each year.  Thus they are not infrequently seen still.  They seem to be of about the same pattern, i.e., pewter Pint Tankards with glass bottoms.