Number of reloads effect impact

[jtkratzer]

If you are trying to be consistent, it makes sense that you try to eliminate as many variables as you can with EACH and EVERY loading. Trimming the cases to the same length for each loading is one you probably don't want to overlook. Trimming only when things get over max is going to give you a variable each time you load from the previous load in that same case. The brass is going to change one way or another, as stated, because it "grows" and you trim it, but the brass you trim has to come from somewhere...

If you are shooting some form of a match and fire 100 rounds in the match, you'd probably get more consistent results if you used 100 cases that were all fired the same number of times and prepped the same way rather than mixing your "lots" of brass.

 

[Bart B]

If you are trying to be consistent, it makes sense that you try to eliminate as many variables as you can with EACH and EVERY loading. Trimming the cases to the same length for each loading is one you probably don't want to overlook.

I've no concern about each and every case be the exact same length from case head to neck mouth. That's not going to put the case mouth at the exact same place in the chamber neck unless the case headspace (for bottleneck cases) is at near zero tolerance. As brand new cases will shoot 1/2 MOA at 600 yards and 5/8 MOA at 1000 in spite of all their numerous variables in case headspace and case length, it's a waste of time to make all resized cases have the same length.

If someone shooting sub 2/10ths MOA groups at 100 yards (at the worst) has ever made proper tests for a 1 or 2 thousandths spread in case length, post your data. Othewise, that tight of tolerance specs is a myth.

I'd rather be consistant in the things about a case that's really important such as keeping its head square with the case and chamber long axis. And loading tools and processes have nothing to do with that.

 

[jtkratzer]

I've no concern about each and every case be the exact same length from case head to neck mouth. That's not going to put the case mouth at the exact same place in the chamber neck unless the case headspace (for bottleneck cases) is at near zero tolerance. As brand new cases will shoot 1/2 MOA at 600 yards and 5/8 MOA at 1000 in spite of all their numerous variables in case headspace and case length, it's a waste of time to make all resized cases have the same length.

If someone shooting sub 2/10ths MOA groups at 100 yards (at the worst) has ever made proper tests for a 1 or 2 thousandths spread in case length, post your data. Othewise, that tight of tolerance specs is a myth.

I'd rather be consistant in the things about a case that's really important such as keeping its head square with the case and chamber long axis. And loading tools and processes have nothing to do with that.

My twice fired cases, trimmed, put a 3 shot group into 0.174" at 100 yards out of a 20" factory Model Seven tube. Some bedding and a trigger job, otherwise, it's as it was in 1997 shipped from Remington. Sizing and trimming has improved the consistency compared to brass straight out of the bag. That's Remington brass, not Lapua or Nosler, which is probably better from the start in almost every case.

Working the primer pockets and flash holes might even do better...I haven't shot factory brass without sizing and trimming it first, but I can't see how it would hurt, especially when putting a light crimp on the bullet. Trimming seems to be more important when crimping. With groups like that, with 2,900 fps, I'm content with this little .260 for a PA deer gun that's under 8 lbs for walking around.