The Maxim

The inventor of the modern self-reloading gun, or machine gun, was Hiram Maxim. In this ATL Maxim dies in a accident in 1865 at his uncle's workshop when a steam boiler explodes. Thus the fully-automatic gun is not developed in time for WWI. Military doctrine remains roughly unchanged into the 20th century.

Note (The Maxim)

Impact Pre-19th century
Colonial Wars (The Maxim)

Weapon development 18th century (The Maxim)