Guns are a creepy tool! I don't like them. They're designed to kill. So I don't wanna design more of them. I'll leave this here though for now. As a "thing" to design, they're a challange. I kept it silly here, but it's weird, remembering what guns are.
A modular gun concept with a "naked" gun-base that needs different outer shells to become whole. This allows different aftermarket manufacturers to make different cosmetic shells, while keeping the functional part of the gun reliable. The default shell, seen first below, leaves such options desirable.