Good and over built but miss leading - Cross Armory Big Bolt Catches

I bought this for an ar10 build. It does not work. At least for an aero ar10 lower. It was flush against the ar10 lower and didnt pivot at all. This is the only reason I didnt do 5 stars. I put it on one of my ar15 lowers and worked great. It is a little bulky, but functions great. It seams to hold the BCG to the rear a lot better then the magpul bad lever. I like the bad lever system, but it always bugged me that it was a little bit of a slacker. If you shook the rifle, the bolt would send home. This bolt catch holds the bolt unless you hit the rifle, which is predictable and there for fine by me.