I could not find any brass for a 500 S&W, the first that came available was some Magtech so I bought it. I am beginning to work up some loads and began having some difficulties in getting rounds to chamber. The ones that did shot fine. I checked the sizer die- a lee product, it seemed to be maybe a .502 instead of .501, I cleaned the chamber right good, then I checked the brass...... I got a thickness reading that varied from .0135 to .0162. , sometimes on the same case. The ones that had chambered easily were around .0145 without much variation. Have any of you had a similar experience? Any ideas other than can the brass?