Original Antique Brunswick Rifles for sale. The Brunswick rifle was a large caliber (.704) muzzle-loading percussion rifle manufactured for the British Army at the Royal Small Arms Factory at Enfield in the early 19th century. The Brunswick had a two groove barrel designed to accept a "belted" round ball. There are four basic variants of the British Brunswick Rifle (produced in .654 and .704 caliber, both oval bore rifled and smooth bore). They are the Pattern 1837, the Pattern 1841 , the Pattern 1848 and the Pattern 1840 Variant. The weapon was introduced to replace the Baker rifle. The weapon remained in production for about 50 years (1836 to 1885) and was used in both England and assorted colonies and outposts throughout the world.