Gun Barrel

A gun barrel is the tube, usually metal, through which a controlled explosion or rapid expansion of gases are released in order to propel a projectile out of the end at a high velocity.

The first guns were made in a time where metallurgy was not advanced enough to cast tubes able to withstand the explosive forces of early cannon, so the pipe (often actually built from staves of metal) needed to be braced periodically along its length, producing an appearance somewhat reminiscent of a storage barrel.

Another explanation, tied to etymology, states that many very first firearms barrels were in fact realized, during the 12th and 13th centuries, using small storage barrels with their usual metal rings reinforced by leather, hence the barrel name. In fact a set of old French words, some of them staying in modern French, were used as root words for various English terms related to firearms (and storage barrels). The old French gonne (pronounced by a French speaker it sounds approximately as gun does when pronounced by an English speaker) was a small barrel used on merchant and military ships. Likewise a baril was, as early as 1323 (used in Du Chevalier au barisel), and remains now, a big barrel. Moreover the big Tun English barrel is, as stated in Ton, the French old and contemporary tonne barrel.