Small base vs. standard sizing dies

They only squeeze the cases .001" to .002" smaller in diameter in the area 0 to 1/2" above the case extractor groove. One to two thousandths is pretty small to see. Some of them also bump the shoulders.001" to .002" more than regular dies for a little more headspace. In my experience with 7.62 ammo, even regular dies headspace too much "cammed-over" as die instructions often encourage. Best to use a headspace gage like RCBS's or Hornady's and bump less for better brass longevity whichever type of sizer you use.

Consider that if you back off either type of sizer, to bump less, you will also size less at the base area with either sizer, which probably accounts for feeding problems using regular dies. I can't for the life of me understand why RCBS designed their S.B. dies to bump more??? Seems back-asswards to me.

One thing to note though, new factory ammo is smaller still at both measurements (base diameter, and headspace). The nice thing about S.B. dies, is that while regular dies may size enough to feed well in your test of a particular rifle, there is no guarantee, that such reloaded ammo will feed trouble-free in another rifle. Factory loads are the most trouble-free.....S.B. dies come in a close second.

So, full length sizing (the usual for semi-autos) isn't your norm. I don't neck size even bolt actions anymore. First, I don't compete. Second, I don't want ammo good for only one rifle. Third, for my needs I've found it easier to keep symmetry between case necks & bodies by full length sizing, while keeping shoulder bumping to .002" to .003" if possible. Such symmetry between body and neck is most important to keeping runnout to .001" or under. My most accurate .308 loads are sized on the Rock Chucker or Summit with an ordinary expander button, sizer, then rotated a third on the shell holder, resized, rotated another third and resized again. That almost always brings runnout to .001" or less with my LC .762 brass.....and no special Wilson die or arbor press used.......but then again, the bench rest ammo Dangun needs & loads is another animal entirely crafted for one special rifle.

BTW, and Dangun will correct if I have the wrong idea, I've heard that neck sizing isn't repeatable over and over, cases need a full length resize once in a while to reset things. That about right?

Bob: And I didn't mean to allude to me owning several .308's either. But sometimes I get restless and change what I own. Yeah I change channels a lot too. I just don't want to have a ton of SHTF ammo tailored for just one gun.......that I probably don't own anymore when and if that time ever comes! But that's just me.

I would like to have a Garand as a shooter and keepsake......just never saw the right one. Don't have a M1A either.....just a Remington R25 that I'd like to trade off for Ruger's new piston AR10ish rifle. I admit I bought the R25 when Obama Bin Biden got elected the first time......why? Because it was the ONLY AR in the state, and I wasn't willing to wait 6 years for Ruger's. Great sub MOA shooter though.