The 8 inch siege and garrison (light) mortars were most affective within 800 yards but could still be deadly at over 2,000 yards and fired 46 pound shells using 2 pounds of powder. Only around 170 of these were produced, and of those only 73 are believed to have been manufactured at Fort Pitt. Mortars were used to throw heavy explosive shells over fortifications in an arched trajectory and could suppress enemy batteries, destroy barracks and other buildings inside a fort's walls, rain explosive shells down on trenches, and more. The bore measures 8 inches across at the muzzle and approximately 16 inches deep. The muzzle is marked "[star] No 41 1006 lbs. S.C.L. [star]/FORT PITT P.A. 1864." The top of the tube is marked "US." No raised foundry number is visible. It is fitted on a Paulson Bros. Ordnance marked reproduction steel bed.