I figured out what I done at the loading bench that caused my bad day of comp. I double compressed my powder in my cases, I ran them thru the compression die 2 times. From what I can find and I don't know why the powder column expands back about .005 if you let the case sit overnight without a bullet crimped in the case. If you go back and compress it a second time it will stay put, this has been my findings on my cases and the powder I'm using. When I placed the bullets and measured the over all lenght of the rounds some of them were .005 of an inch long, I have shot these in the past without any problem. This time the ones that measured .005 long I ran them back thru the die and did not measure them again, I didn't realize they were now .010 shorter than they were. They were now .005 shorter than my target length.
I found this today when I had loaded up some rounds Tuesday for a test today. I had also ran some of those rounds thru the die twice and did not measure them after the second time. Before I left for the range today I was measuring the length of the rounds and there was 5 rounds short .005 and there was 5 rounds the right length. I sorted the 2 groups and shot them separate at the range at 200yds. The 5 that had been ran thru the die twice had a group about the size of your hand, the 5 that was at lenght or a couple of thousandths long had a 1" group. Same bullet, same powder, everything the same, except they were only ran thru the die 1 time.
Lesson learned today, don't change anything from the standard procedure!! I am glad I found the problem so quickly, this could have been very time consuming and expensive with a lot of trial and error. They've had a bad day at the next match.
SG's Old Coots Den & Privy
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