Battle of the Somme
The soldiers in the trenches used rifles.  Most soldiers used was the bolt-action rifle, which could fire 15 rounds per minute and could kill a person as far as 1.4 kilometres away.  This rifle was invented in the United States by a Scottish man called James Paris Lee. The bolt-action rifle had a metal box where the cartridges were put on top of a spring.  As the bolt opened, the spring forced the cartridges up against a stop and the bolt pushed the top cartridge into the chamber as it closed.  After the rifle was fired, the opening of the bolt ejected the empty cartridge case and the return stroke loaded a fresh round.  The cases held 3, 5 or 29 cartridges each.