The reason given is: Same content, different name. I suspect that this name is an earlier version and was later updated.. You can debate this at the talk page. If nobody objects, go ahead and make the proposed changes.
The Modello 1918 was the first conventional submachine gun to ever be issued to regular troops, and according to some sources the weapon predates the more famous MP 18. The fire-rate was a formidable 900 bullets per minute - or 15 bullets per second. This rapid-firing gun was reported as both durable and reliable and some even saw action during WW2. It is formidable trench cleaning tool.