So far i've lapped 4 or 5 upper receivers. What is you guys stopping points? For me every one i have done shows signs of metal being removed all the way around, so I go til the whole front is shinny. I am using the wheeler lapping tool, http://www.budsgunshop.com/catalog/...235/Wheeler+Delta+AR-15+Receiver+Lapping+Tool. I have seen posts of people only removing a little making a half moon shape and so on, but for me it seems to always be all the way around. The uppers are cheaper Anderson uppers. The first upper I built, not lapped, was a pain getting the gas tube in place/lined up and getting the barrel nut tight, among other issues that were a pain. Every since lapping my uppers it all just fits perfectly. So what is your experience on lapping uppers and when do you say, "That's good"