Wait... I've seen this project before. Don't remember what it was, but it had... giant monsters.... or something? Either way, it's an awesome-looking assault rifle. I like the futuristic aesthetic you used
awesome look... apart from the silencer. In RL a silencer like that is really inconvenient because you have to be careful about knocking it. if it isnt exactly straight, the bullet will graze or hit the silencer wall. most guns that come stock with a silencer have a guard.
wouldn't say ruin, but leads to the correct path of fantasy. You need a lot of failures to get to the correct result. Thus for the sake of having an idea, whether or not it's functional, doesn't matter to me. There can always be a revision update.
Also, I believe that for CQB police would prefer anything smaller caliber then full automatic rifle, like SMG. Or shotgun. Some short weapon to have better maneurability in relatively small rooms and corridors. Also smaller caliber makes less unneeded ricoshet, which may lead to unforeseen casualties among civils. Also less weight also faster pointing of the weapon.