Small base Sizing dies

[mac86951]

Really only time I needed one; once fired Lake City 7.62x51... so, i cheated. Small-base X-Die for my gas gun fun.

Real question is: if you're new to reloading, and you've a gas gun, what would I recommend on your first die set purchase? I'm leaning toward regular dies for caliber and encourage the use of an RCBS precision mic, or other tool to measure how your sizing die is set up. Gas gun, i resize so that the shoulder dimension is approx. 0.002-0.004 from what it measured at when fired. I do wonder; how many small base dies are purchased when a 1/8 turn, or change in shell holder might have been the culprit.

Alternatively, if you're wanting to load MAX loads; or going for MAX pressures, then maybe a small base die is a good thing?

-Mac

 

[Jager]

... I'm leaning toward regular dies for caliber and encourage the use of an RCBS precision mic, or other tool to measure how your sizing die is set up. Gas gun, i resize so that the shoulder dimension is approx. 0.002-0.004 from what it measured at when fired. I do wonder; how many small base dies are purchased when a 1/8 turn, or change in shell holder might have been the culprit.

Alternatively, if you're wanting to load MAX loads; or going for MAX pressures, then maybe a small base die is a good thing?

-Mac

Small Base dies don't have anything to do with shoulder bump, shoulder dimension, or die setup. What they do is provide a smidge more constriction at the base of the cartridge, just above the web. Ergo the name.

And there's no reason I can think of why they would be good, bad, or indifferent with respect to pressure. When I'm running a pressure model the kind of FL die I use isn't a factor.

 

[dkhunt14]

Since the OP didnt specify cartridge...
I've found if your going to really push a 338 Edge + P, 338 Lapua AI, Or 338-378 Weatherby AI to thier limits, a small base die may be reqiuired sooner or later. Except maybe in the Lapua if your using Lapua brass.
I sent 3 pieces of brass to John Whidden to make die for the 338-378 Weatherby AI. Called me to ask if I had an insert in my press. I do so he said he has had problems with dies made for those and wants to make 1 1/4" small base die right off the bat cause I am going to need one shooting the available brass for that cartridge. Probobly get by in the Edge if making brass from Remmington brass, ADG or Norma got two firings before wouldn't chamber, without mallet. And even then some primer pockets loose after several firings.

The real lesson is if Lapua (or now Peterson and Alpha) don't make brass for it, I'm going to pass on it.

I have one AR shooting Lapua brass that needs sized with SBD every fourth sizing. other than that the 223, 308, 30-06 SBDies been chilling out in the cabinet since i inherited them a looooong time ago.

I bet the problems with the smaller diameter die is because of the diameter of those fat cases. Not enough metal in the die to resist springing or cracking. The smae thjjng can happen if your tenon in the barrel is too small, thise big cases allow the barrel to swell and when it comes back, extraction can be difficult. Matt