For two reasons, canister shot fired from rifled guns was less effective than canister fired from a 12-pounder Napoleon or a M1841 12-pounder howitzer. First, the rifled gun's 2.9-inch or 3-inch bore was narrower than the 12-pounder's 4.62 in (117 mm) bore and could hurl fewer canister balls. Second, the barrel's rifling caused the canister to be blasted in an irregular pattern. Union General Henry Jackson Hunt believed that the range of canister fired from rifled guns was only half the 400 yd (366 m) effective range of canister fired from the 12-pounder Napoleon.