[Unclenick]

I sure understand all that. I often post in detail in part so strangers lurking in the forum won't try to copy something without understanding it.

I own lots of benchrest type loading tools even though I don't shoot benchrest. I found years ago that some guns would turn out to be picky about something unexpected, though. One year I was playing around with shooting Accurate 2520 in my M1A and was having trouble getting consistent groups. The gun would should about 0.7 moa with 168 grain Sierra MatchKings in any tuned stick powder load, but was about 1.25 moa with 2520. When I was working on the loads one day, I accidentally picked up some cases that I had carefully prepped for a Remington 600, and discovered the M1A groups shrank to the same 0.7 moa I could normally get from it with stick powders. By eliminating steps one at a time, it turned out to be flash hole deburring that was doing the trick. It never made any difference to my stick powder loads, but it did to my 2520 loads.

Ever since then, I've used every trick I could find to eliminate all variables except the one I'm controlling for the load development. That usually lets me find a load that doesn't need much done to it, but which would have been a lot harder to identify without having started out as perfect as possible. There's a mathematical reason this is true that has to do with the way standard deviations add.