[lugerholsterrepair]

Roadkill is correct. Principally it was the development of the Maxim machine gun. Barbed wire was used mostly in the trenches and the trenches came about when major movements were prevented. Cavalry moved in the open where machine guns were very effective in tearing them apart.

The early tanks were used in the trenches to tear out barbed wire and use their on board machine guns to shoot down the terrified infantry in front of them who would either attack the metal monster or break and run. Attack with rifles or machine guns was inefective due to armor plate. Ah, The joys of modern warfare! Jerry Burney