Altered Pattern 1842 .758 inch calibre percussion rifle musket, 1854

Manufacturer of lock, Tower; Contractor (conversion to rifling), Pritchett.

Although the introduction of the rifle musket and the expanding bullet rendered the smoothbore musket obsolete, it was feasible to convert the smoothbore to the new system. During the early months of the Crimean War (1854-1856) many Pattern 1842 Muskets which had remained in store in Britain were converted into rifle muskets, for issue to the Royal Navy and Royal Marines only. Rifling grooves were cut into the barrel, producing a new weapon that was designated the altered Pattern 1842 Rifle Musket. The process of rifling the bore enlarged the calibre from .753in. to .758in. and it fired a large conical-shaped bullet fitted with an iron cup, of Pritchett design. The bayonet for the Pattern 1842 musket was also used for the rifle musket.

The first order for the conversion of 1,200 Pattern 1842 Muskets was made in April 1852; further orders were to follow. The conversions were rifled with either four grooves, like the Minié, or with three grooves, as with the Pattern 1853 Enfield. This example has three rifle grooves and is sighted to 1,000 yards (914 m.). Externally the weapon is very similar to the Minié, but because the increased weight of the bullet (about twice as heavy as the Pattern 1842 Musket ball) gave it such a fierce recoil, it proved very unpopular.