Wiard described two calibers: a six-pounder rifle with a 2.6 inch bore and a twelve-pounder smooth bore with a 3.67 inch bore. The six-pounder's tube was 53 inches long, weighed 725 pounds and had an effective range (at 35°) of 7000 yards, with a standard powder charge of 0.75 lbs and 6 lb. Hotchkiss bolts. Other innovations included a flat trail plate with a metal keel (preventing the rifle digging itself in the ground upon recoil), and a better system for braking the carriage without damaging the iron tires.