Uncle nick, I think a standard full length sizing die for a belted cartridge could have its bottom cut off and squared 1/10 inch above its case belt clearance shoulder then its edge barely rounded and smoothed. Then do the same thing just below the die's body-shoulder junction. Set the die in the press so it body sizes a previously full length sized belted case all the way to the belt. If it doesn't size the body right in front of the belt back to about new case diameter, cut more off its bottom.
This is how folks in the '60's made them. I made mine from a .30-.338 FL die and it's been well used on several belted cases with similar body tapers. We called 'em "belted case body dies" back then.
On headspace gauges for barrel chambers.....
I made a set of them in .001" increments for .308 Win. chambers. First, I full length sized some fired cases such that their case headspace ranged from 1.631" to 1.636" or thereabouts. Then put each on in a Wilson case trimmer reversed and squared up their heads just enough so they measured 1.629" to 1.634" in .001" steps on my RCBS Precision Mic with my Forster 1.630" GO headspace gauge as a reference. Then I filled them with plastic steel to the case mouth. With a stripped bolt, they could be used to see what a chamber's headspace was within .001" of exact as long as the bolt handle dropped from its own weight snugging up on the case head. That brass case would shorten its headspace .001" or more if I forced the bolt closed on one so that epoxy inside made them less suseptable to shoulder setback.
Last edited by Bart B.; November 30, 2012 at 04:33 PM.