Thank you all for the good advice. I did have my sizing die set up wrong for sure. I didn't read the RCBS directions because I've done it so many times but it's been a few years since I set up a set of dies for a new cartridge.
As for as my gunsmith, I know what he will say, 'I told you not to use cheap brass and you need to get a set of match grade dies" because I've heard him say that before. He's a serious accuracy freak. I went to the range this morning and fired 16 rounds (got one 3 shot 1/8" group at 100 yds, so no problem there). I did use Lapua brass and none of them failed to chamber.
Since the guy who built this rifle is here in town, if it ever happens with Lapua brass I'll head straight to his shop and get him to show me what's wrong.
Thank you all again.
