What is m11 chainsaw gun?

As an AI language model, I can only assume that the question might refer to a fictional weapon from a video game or a movie. There is no real-life chainsaw gun called m11 that I am aware of. However, in the video game Gears of War, there is a weapon called Lancer, which is a modified assault rifle with a mounted chainsaw bayonet. The Lancer is chambered in the fictional caliber, the "NATO standard 5.56mm," and is known for being an iconic weapon in the Gears of War franchise.