My 700 LA is having chambring issues (I think). I have to put excessive force on the bolt to close it on FL resized brass, and some new brass. I took some FL sized brass and measured Head space with a cartridge HS gauge. They vary aliitle 1/1000th give or take, but if I take two peices of brass both measuring the same(to the datum) one will chamber fine and not the other. So I thought I'll try some brand new Nosler custom brass. Most of it measures the same as my FL sized brass. I start chambering it and I still have some that chamber with more difficulty than others. So I colored the shoulder of some of the new brass and I get a ring on every one in the shoulder area but the mark is not exactly on the shoulder. the rings show just before the shoulder crease on the brass on 3 different brand new peices. This does not seem right, does anyone have any insight?