Quote Originally Posted by 1hole View Post
It's luck. It's not a matter of die brands, rifle brands or case brands, as such. Everything made by man has a range of "in tolerance" dimensions, usually just a few thousanths in each direction, and all brands follow the same SAAMI specifications so it doesn't matter what color die box you buy. Thus, it's pure bad luck if your tools stack tolerances toward the "too tight" side for your snug chamber. And slightly soft cases accelerate the swelling that can lead to chambering difficulties. But, most magnum reloaders will never experience that problem so they don't need a solution.

I don't have a belted case rifle in my safe and never will, but I reload for a few friends who do. When one guy started having trouble chambering his several times reloaded cases I checked his chamber and FL sized case dimensions just ahead of the belt. I found his sticky cases were at max plus 1/2 thou above SAAMI diameter and his chamber was on the small side of SAAMI; a half thou is close but it's a lot of metal-to-metal difference when pushing on a bolt!

That was some 40 years ago, the excellent Willis collet sizer die wasn't available back then. I found a yard sale set of magnum dies and modified the sizer so it would squeeze the cases a tad more above the belt, about 2-3 thou smaller than the original sizer did; that fixed it.

SAAMI max diameter above the belt is .512". I lathe cut off the bottom of the die until the belt relief was gone and the internal diameter was .510". Then I ran a cheep 1/2" carbide concrete drill bit (to cut the case hardened steel) down from the top and stopped it about 1/8" above the bottom of the die, then smoothed and polished the exposed hard cased skin, inside and out. I push the cases into that die to just kiss the top of the belt, it puts the loaded belt bulge down to the middle of the SAAMI case tolerance range and everything works fine.

Wish I'd thought to market it. Never guessed it was a common enough problem to sell my "invention". Oh well, I still have my Social Security check coming in so what's another million $, more or less. ??
Nice description of Tolerance Stacking, most people don't understand machining principles or how 1/2 thou here a thou there adds up down range (1000 thousandths of inch at the muzzle is 3.6 inches at 100 yards) I believe the most accurate rifles are built not bought.