The MP 18 made its combat debut during the First World War. Standard-issue bolt action rifles of the era were in no way optimized for trench warfare. They were optimized for engaging an enemy at a couple thousand meters and had long barrels to accurately meet ranged targets. This made them a rather poor choice for narrow, cramped trench conditions, as did full-power rifle cartridges.
Compounding the overpower issue, European standard-issue rifles were bolt action and had a limited capacity, usually a paltry five or seven cartridges. The MP 18 on the other hand was perfect for the trenches.
It was issued primarily as a trench-clearing weapon optimized for close combat. To this end, the MP 18 had a very high magazine capacity for its time. Using the standard-issued 32-round drum, or rather snail, magazine, the MP 18 was markedly superior than any bolt-action rifle at ranges of 300 meters or less.
During the turbulent inter-war period, a number of German paramilitary groups used the MP 18 with great effect in urban battlefields, which shared a number of the same characteristics as the trenches of the previous decade, namely tight, confined fighting at short distances.
One of the few drawbacks of the MP 18 was its weight when loaded. The drum magazine it sported made the gun somewhat unbalanced and was difficult to fully load by hand without using a special purpose-made loading tool. For a submachine gun it was very heavy—a whopping 11 pounds, or about 5 kilograms with a full 32-round magazine inserted.
The drum itself was also somewhat problematic—a stay had to be fitted to the drum to prevent it from being inserted too far into the MP 18’s receiver. The MP 18 also lacked a safety. If accidentally dropped or firmly hit, the gun could unintentionally discharge.
Initially a fully automatic-only weapon, the MP 18 could only fire single shots through careful and purposeful quick trigger pulls. Some post-World War I variants were given a fire selector for semi and fully automatic firing. Some were also given bolt lock-type safety that would prevent the MP 18 from accidentally discharging.
The Brits made a direct copy of the MP 18 after their harrowing and miraculous escape at the Battle of Dunkirk in 1940. Realizing that the British Army had no weapon that could fill the gap between machine gun and rifle, a crash program was instituted to copy the MP 18 directly. The resulting Lanchester submachine gun was in some ways superior to the original and had a solid, high-quality design.
A modified MP 18, the MP 28, saw limited service into World War II with some Wehrmacht soldiers.
Caleb Larson holds a Master of Public Policy degree from the Willy Brandt School of Public Policy. He lives in Berlin and writes on U.S. and Russian foreign and defense policy, German politics, and culture.