BB2 X tra
This is a pretty common problem with these heads. Either start working on the domes where it hits. Or do what I did made the chamber look like a Dart chamber. Mine hit with a set of Ross pistons.
This sure sucks, but not much to do but fix the problem. I went round and round with Brodix, and Ross. Sent pictures to both of them. Neither one did anything about it!
Good luck!!!!!