Springfield musket, ca. 1848
Muzzle-loaded muskets like this, with a bayonet that could be attached, were common during the Civil War. Most were rifled, helping to propel the bullets.
Soldiers bit the end off the paper cartridge that held the iron ball and gunpowder, poured both into the barrel, used a ramrod to seat them, and added a percussion cap under the hammer. The weapon was then ready to fire.
The initials "DV" are carved into the stock.