Brown Bess was the colloquial name for the 0.75 calibre flintlock musket which was the standard British military long gun from 1728 until the middle of the 19th Century. As such, it was the most common long arm in use by both sides at the start of the American Revolution. It was officially superseded by a percussion version of the musket in 1842, although some were still in service during the Indian Mutiny of 1857.
The origin of the name is unknown. It perhaps derives from the German büchse, for gun, or the Dutch bus for barrel (hence blunderbuss) or maybe from the colour of the walnut woodwork.
Stress-bearing parts such as the barrel, lockwork, ramrod and sling-swivels were made of iron; the other parts such as the butt plate, trigger guard and ramrod pipe were brass. It weighed around 10 pounds. It could be fitted with a 17-inch triangular cross-section bayonet.
It went through numerous variations and modifications over its long history. The first common version was the Long Land Pattern of 1730, 62 inches long with a 49 inch barrel. It was eventually discovered that shortening the barrel did not detract from its accuracy (which was extremely poor anyway), but was easier for soldiers to manage. This resulted in the Militia (or Marine) Pattern of 1756 and the Short Land Pattern of 1768, both of which had a 42 inch barrel.