Looks very sci-fi and scary. No way I'd want to be on the receiving end of that thing.
Since these are concept pieces for an IP, I guess what you can do with them is limited, but are you familiar with Satellite Reign? It's a Kickstarter project that got funded a while ago and the focus is on making a successor to the original Syndicate series. If you're able to, these might be some weapon designs that they'd love to see since their setting is very sci-fi, dystopian, and gritty futuristic. Just as a suggestion.
Regardless, this is an awesome weapon. I can only imagine the kick it would have. And having the details in the corner there makes it feel that much more real. Excellent job!