I previously left a bad review, but it turns out the grip was just super tight - Bravo Company AR-15 Enhanced Lower Parts Kit

All of the parts in this kit work. I managed to get the grip on. It has been a while since I built an AR-15 and I don't recall the last grip I ever installed being as tight as this one is. I suppose it is a good thing that it is tight since there won't be any movement. If the screw came out it would probably stay on for many more shots lol. I'm not sure if the grip is supposed to be that tight, but I did get it to work. All in all, this kit is definitely worth getting for your next AR build. I take back what I said about OP as in the moment it seemed as if a low quality product was being knowingly pushed, but it does work. just keep wiggling it until it goes on if you have the same issue.