Here goes, bought a BM dissy upper from a gun dealer. I was told it was new and appeared so. He sold it to me for a good price cause it didn't match finishes with other guns so noone really wanted it. I took it home and fired it several times...about 300 actually. No problems with function at all just would not zero properly and it seemed the grouping was iffy. I kinda felt let down, most AR15s I have shot were tight. I called BM tech support about the windage problem. I talked to a VERY VERY nice lady on the phone. She gave me a number and I sent it in to be reindexed. I mast make a minor complaint here though, I used USPS to send it in and it only took them 3 business days to get it there and when BM sent it back to me they used UPS and it took twice as long to get it from them. BM did do a speedy job as far as the gunsmith working though, I must admit. I shit it this afternoon when I got home and I was impressed to say the least. The grouping tightened way up. Even with suck wolf ammo. I sent 3 rounds down range while looking through a cheap leapers scope at 125 yds and managed just under 1 inch group!!! Hell yea!!! I can only imagine what a good scope will do. They didn't thread the barrel like I asked...but they aren't doing anyone else's either. I even offered to buy their most expensive FS to no avail. Guess someone else can use that money more though. But I have to give their gunsmith credit for a job well done on that one. So hey BM guy if you read this tell you gunsmith I said thanks and well done OK!