The 3-inch ordnance rifle, model 1861 was a wrought iron muzzleloading rifled cannon that was adopted by the United States Army in 1861 and widely used in field artillery units during the American Civil War. It fired a 9.5 lb (4.3 kg) projectile to a distance of 1,830 yd (1,670 m) at an elevation of 5°. The 3-inch rifle was not as effective in firing canister shot as the heavier 12-pounder Napoleon, but it proved to be highly accurate at longer ranges when firing common shell or spherical case shot. There was only one reported case of a 3-inch ordnance rifle bursting in action. This was in stark contrast to the similarly-sized cast iron 10-pounder Parrott rifles which occasionally burst without warning, inflicting injury on the gun crews. The Confederate States of America lacked the technology to manufacture reliable copies of the 3-inch ordnance rifle. However, the Confederate States Army respected the weapons and employed those captured from Federal forces.

The M1857 12-pounder Napoleon or Light 12-pounder gun or 12-pounder gun-howitzer was a bronze smoothbore muzzle-loading artillery piece that was adopted by the United States Army in 1857 and extensively employed in the American Civil War. The gun was the American-manufactured version of the French canon obusier de 12 which combined the functions of both field gun and howitzer. The weapon proved to be simple to produce, reliable, and robust. It fired a 12.03 lb (5.5 kg) round shot a distance of 1,619 to 1,680 yd at 5° elevation. It could also fire canister shot, common shell, and spherical case shot. The 12-pounder Napoleon outclassed and soon replaced the M1841 6-pounder field gun and the M1841 12-pounder howitzer in the U.S. Army, while replacement of these older weapons was slower in the Confederate States Army. A total of 1,157 were produced for the U.S. Army, all but a few in the period 1861–1863. The Confederate States of America utilized captured U.S. 12-pounder Napoleons and also manufactured about 500 during the war. The weapon was named after Napoleon III of France, who helped develop the weapon.