I have been learning my gun and the right load. I have a Savage 12F/TR I have about 400 rounds through it and found It shoots 42gr of Reloader 15 with 168grMK the best. I have tryed all types of power and primers and a boat load of bullets. You guys have help me find the right seat depth and .010 off the lands seems to be the sweet spot. Here is what happend at the range this weekend I was shooting at 300yd and trying differant loads and I was checking my brass and found some of the older rounds that I reloaded with WIN brass at the edge of the shoulder it had some deep marks in the casesand it was only found on Win brass. I had 20 rounds of Lapua Brass with the same loads and it look fine. Is It something I am doing wrong are bad brass. How is the best way to check the chamber of my gun? Could it be the problem. The Lapua brass was new, but I did full size the brass and trim to spec before reloading. I did use differant dies with the lupua brass I used RCBS COMP DIES. I thought it maybe the dies I was using when I reloaded the Win brass??? If this is a normal thing please tell me..