Re: Explaining Headspace
You've got a half-inch difference in the length of your brass? I think you typed some numbers wrong.
First, ignore that comment about "if you shoot a lever, don't full-length resize". That's nonsense. You can get away with neck-sizing on a bolt gun or a single-shot, but anything else needs full-length resized.
Second, you can only get away with neck-sizing if it is going to be shot in the SAME GUN. If you have ONE 308 bolt gun, and you fire new shells in THAT 308 bolt gun, then the brass is fire-formed to THAT chamber. You can then neck-size the brass that will be loaded to be fired in THAT gun. There is no other gun in the world that has that exact size chamber. NONE. NOWHERE. So if you neck-size brass shot in THAT 308 bolt gun, and then try to put the loaded ammo into THIS 308 bolt gun, there is a good chance that it will not fit.
Now, as I understand your post, the brass you have is stuff fired in YOUR gun, stuff fired in YOUR WIFE'S gun, and stuff that has been given to you or that you found at the range. In other words, NOT ALL FIRED IN THE SAME BOLT GUN OR SINGLE SHOT. It needs full-length resized.
Once it has been full length resized, it will fit in any gun of that caliber. If you plan to neck-size after that original full-length sizing, definitely keep your brass separated from your wife's brass.
If your gun is NOT a bolt or a single-shot. If it is a lever, a pump or an automatic, ignore anything anyone tells you about the joys of neck-sizing. It will just cause you pain and heartache, trying to make it work.
Meddle not in the affairs of dragons, for thou art crunchy, and taste good with catsup - George of Lod, Year of Our Lord 297
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Beware the Evil Bullet Fairies.