Arquebusier

The arquebus (/ˈɑːrkᵻbʌs/ ARK-ə-bus or /ˈɑːrkwᵻbʌs/ AR-kwə-bus) (sometimes spelled harquebus, harkbus or hackbut; Italian Archibugio, Dutch haakbus, meaning "hook gun", or "hook tube") is an early muzzle-loaded firearm used in the 15th to 17th centuries. An arquebus was originally a gonne with hook, and later a matchlock firearm. Like its successor the musket, it is a smoothbore firearm, but was initially lighter and easier to carry.

It is a forerunner of the rifle and other longarm firearms. An improved version of the arquebus, the caliver, was introduced in the early 16th century. The word is derived from the English corruption of calibre as this gun was of standard bore, increasing combat effectiveness as troops could load bullets that would fit their guns (before, they would have to modify shot to fit, force it in, or cast their own before the battle).

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Wikipedia