Browning Auto-5 (abbreviated as Auto-5 or A-5, meaning "Browning 5 shotgun") is a semi-automatic shotgun designed by john browning, a famous American gun designer, and operated by the back seat. Can launch 12 caliber shotguns and 16 caliber shotguns.
Auto-5 is the first semi-automatic shotgun mass-produced in history. It was completely designed by john browning in 1898 and patented in 1900. Large-scale production started from 1902, lasted for nearly 100 years, and was produced by several gun factories until 1998.
It adopts a unique high tail design, which earned it the nickname "humpback". The bolt motion at the top of the Auto-5 will not be directly transmitted to the front of the barrel. This design can greatly reduce the recoil on the stock and improve the firing rate.