The big thing I didn’t see mentioned is development. In the civilian world the drive is essentially to get a reputation as a game killer, or target whacker. Not really all that hard to do... beat 3000fps and put a pointy nose on it and make it expand like crazy when it hits a target. In military use though, there is a lot more development. Short range, long range, armor... hard, heavy, soft, light... bolt rifle, semiauto, full auto, belt fed... hot, cold, wet, dry, beat to hell, covered in mud...
With all that being done extensively, why not use it for something in a civilian world.