For those of you who didn't open the workshop link:
Wow this is sick, I'm so into this. I think it's a little too difficult to react to, and would have too much overlap with the gauss rifle. It's also pretty out of place. I like that you can't really hold onto it without giving yourself away, though I could also see it causing rdm for people killing based on the sound if someone has it in their pocket in a crowd.
Ignoring the fact that it's out of place, this could be balanced and not too similar to the gauss rifle perhaps if it's 3-4 uses but does about 45 damage in the entire area it hits (unlike the gauss rifle which on SGM was 2 shots, lethal on a direct impact, but has harsh damage falloff over the rest of the area it hits). I generally like the idea of giving traitors an option for long range explosive damage in the credit shop.