Does one method end up with bullets better centered in the bore when fired? If so, why?
THIS... AND to back up what he said, if you don't skim turn and square up the necks to true them, I don't feel either method has any effect on accuracy whatsoever as long as they are sized properly. In fact, there is a faction that believes if you don't prep your brass you are actually better off using small base dies and completely sizing cases back to nearly new factory dimensions. They feel this allows the case to self align in the chamber somewhat, like a factory round. For our purposes (a long range precision rifle) I feel very strongly every round of brass should be fully prepped and sorted. Great loads cannot be either consistent, or duplicated without this step. Leave this step out and you will always be chasing your tail for accuracy. You can find a load that shoots the magic 1/4" group. Go home and load up a bunch and the next group just may be 1-1/4". Doesn't take long to turn, trim and chamfur the necks, ream the flash holes and primer pockets on 100 cases. Doesn't take long to sort them by weight either. I don't sort them until they have been fully prepped.In my opinion Yes.
But there is more to centering the bullet than just neck sizing. cases need to be prepped and turned before they are ever fired. Then with minimum sizing or Neck sizing the chamber will hold the cartridge in perfect alignment. The concentricity of the loaded ammo also has a bearing on centering the bullet.
So keep In mind that one or the other method may not be any better if all the other conditions are not dealt with.
J E CUSTOM
Most target guys FL size now days.From a hunting stand point I always full length, just do not want to risk a loading problem. I never jam the bullet either. If I was a target guy would likely neck size.
I'm interested in the point you're getting atWhere is a rimless bottleneck cartridge in the chamber when the primer fires?
A. Held against the bolt face by the extractor.
B. Resting on the chamber bottom.
C. Pushed into the chamber shoulder by the firing pin. And the bolt face ejector, if used.
If the cartridge's outside dimensions are smaller than the chamber dimensions, its position in the chamber determines the bullet's alignment to bore center when fired. External forces on the cartridge determines its position when fired.I'm interested in the point you're getting at
Assuming headspace is correct, the shoulder of the case is slightly wedged in the chamber. neck has slop. case body has slop. To me, it seems the most important part is the face of the shoulder having light contact with the chamber.Where is a rimless bottleneck cartridge in the chamber when the primer fires?
A. Held against the bolt face by the extractor.
B. Resting on the chamber bottom.
C. Pushed into the chamber shoulder by the firing pin. And the bolt face ejector, if used.
Most target guys FL size now days.
It seems neck sized would line up better because the .010" of slop from case walls to chamber wall would be taken out. It doesn't seem to improve accuracy.
I think a 2 to 3 ounce firing pin pushed near 20 fps by a 25 pound spring force would very tightly press the case shoulder into the chamber shoulder. Sometimes setting the case shoulder back a couple thousandths.Assuming headspace is correct, the shoulder of the case is slightly wedged in the chamber. neck has slop. case body has slop.
Walls will have .010" ish slop