6.5/.284 die - brass question
Hi. I recently got my stick back from rebareling and I have a question about a load. Off the bat I tried some 142 MKs over 46.0 RE19 out of Lapua brass. I usually run new brass through sizer to make sure it's to spec. but this time I tried some out of box. The rifle shot in low .2s and even .1s with no brass prep at all, and those were 4 and 5 shot groups at 100 yd. After running the brass through full sizer and reloading, I can't get it to hold under 1" at 100. I switched bullets, powder, primers, went up and down the charge scale, but to no avail. Checked the rifle all out, it seems fine and tight. Dies are Hornady Custom New Dimension. Rifle has Douglas 28" match barell on a pre-64 M70 in a H-S stock with Leupold on top. After I loaded some unsized brass from the box, groups went back to one hole. What gives...? BTW I'm no benchrest or tactical shooter, just like to shoot some groundhogs.
TX in advance.