I don't know any but will pass this along, if you're planning on putting on BUIS's, make sure they're steel. MagPul makes some good ones but they're made of some kind of polymer that won't hold up to the heat. What brand/model did you get? Too bad you couldn't get that M&P. I paid about a hundred and a half more for mine. If I hadn't bought a few guns lately, I might have jumped on that myself.