Load-to-load variation
kart racer, I'll echo the statements of the others. When I first got my Oehler chronograph, I was speed checking everything in sight. I finally settled down and did some (fairly) serious research. One of the first projects was to explore the difference made by different cases.
I found that the variations were very much on the order of those given by
Bigslick in Post #10, above. I had purchased about 3,000 once and twice fired .45 ACP brass from the estate of an old bullseye shooter. About half of these were old cases headstamped REM-UMC. These had noticibly thinner case walls than some others, especially WCC military cases and Speer commercial cases. The REM-UMC cases didn't even want to hold jacketed bullets firmly, but were fine for lead round nose. As a result, I sorted brass and held out the thicker-walled stuff for my "premium loads," for hunting and matches.
Like many who really enjoy shooting pistols, I engage in a variety of activities. I fire at least 50 handloads for every centerfire factory round - -possibly a hundred. I guage every round by dropping it into an extra barrel, and cull out all which do not
click when they go into the chamber. Unless I'm putting up ammo for weapons accuracy testing or for a match in which some precision is needed, I don't bother sorting by headstamp. There's no reason to spend the additional time on ammo used to practice speed drills at close range, or which will be fired in an open-bolt submachine gun.
OTOH, if some cross-canyon rock slaying is pending, I carefully sort out my amo by headstamp and apparent age of brass, and it makes the two and three hundred yard hits far more likely. There's a certain satisfaction in whacking a two-foot square rock at distance with a good .45 autoloader. Long range handgun shooting is not the
exclusive province of magnum revolvers and scoped single shots.
The above comments apply only to my handgun loading. I become fairly compulsive about uniformity, case length, and case weight when putting up rifle loads. But that's another topic.
Good shooting to all
Johnny