Wouldn’t it be a noisencer? It isn’t a quietencer, afterall.

Put that on a 50 bmg pistol. You could probably blow peoples ear drums at a distance with blanks.

“And this is for shooting down police helicopters”

One of my old favorite reddit threads about making a stupid loud gun

https://www.reddit.com/r/guns/comments/c2iyvl/i_am_become_deaf_destroyer_of_ear_drums/

There is kinda that thing actually in usage. The German MG3 uses a recoil system to cycle the next round. For better operations they have a recoil enhancer at the end of the barrel that kinda looks like this.