in my post here:ar15.com/forums/topic.html?b=3&f=118&t=163703
i describe a problem wherein an aftermarket part won't mate with my BM lower. it would appear from a follow-up posting that the hole in the BM lower is "out of spec" by a few thousandth's of an inch -- but it's enough to make a difference. any comments? i do think that KAC also erred, since their part is obviously oversize as well.
jim aka ar-jedi