Small Base vs Standard Die

[r bose]

Get the small base die, it will likely solve your problem. One possible cause of your problem is a chamber that is smaller than your current dies can accommodate.

That's the only solution I could think of also. So I'm assuming I should use the SB RCBS die every time I resize?

 

[Uncle Ed]

r bose

Right now I'm sizing 250 once fired Lake City 7.62 cases and I experimented with a standard Lee full length .308 die and a RCBS small base die. And the standard Lee die reduced the case diameter as much as the RCBS small base die did.

Chambers and dies vary in size and you might have a skinny chamber and a fat die. And the only way to find out what your die is doing is measure the fired case at three points along the case body and again after sizing. Dies have plus and minus manufacturing tolerances so its a coin flip when you buy a die.

I have a JP Enterprise case gauge that is made with a finish reamer cut to minimum SAAMI dimensions. And if the case passes a plop test into the gauge the sized case should fit in any chamber. I do not use this gauge to check headspace and only use this gauge to check case body diameter. This is because these once fired cases were fired in larger diameter military chambers and I'm checking for brass spring back after sizing.

"JP Enterprises Case Gauge Cut manufactured from actual match chamber finish reamer. JP Enterprises Case Gauge checks head space and case diameter. It is the only case gauge from JP Enterprises that checks minimum and maximum for headspace, case length and case diameter."

 

[338rumshooter]

Just picked up a lyman small base die set for a 458 socom which I was not pleased with, so I replaced it with a Redding standard die. The standard die sized almost .002 tighter than the small base, using the same shell holder. Going back to the fact that there might not be a standard for small base.

 

[r bose]

r bose

Right now I'm sizing 250 once fired Lake City 7.62 cases and I experimented with a standard Lee full length .308 die and a RCBS small base die. And the standard Lee die reduced the case diameter as much as the RCBS small base die did.

Chambers and dies vary in size and you might have a skinny chamber and a fat die. And the only way to find out what your die is doing is measure the fired case at three points along the case body and again after sizing. Dies have plus and minus manufacturing tolerances so its a coin flip when you buy a die.

I have a JP Enterprise case gauge that is made with a finish reamer cut to minimum SAAMI dimensions. And if the case passes a plop test into the gauge the sized case should fit in any chamber. I do not use this gauge to check headspace and only use this gauge to check case body diameter. This is because these once fired cases were fired in larger diameter military chambers and I'm checking for brass spring back after sizing.

"JP Enterprises Case Gauge Cut manufactured from actual match chamber finish reamer. JP Enterprises Case Gauge checks head space and case diameter. It is the only case gauge from JP Enterprises that checks minimum and maximum for headspace, case length and case diameter."

Looks like this ^^^^^^^ will be my next purchase. Ironically, I have a Lee set in 308 that I used for many years loading for my M1A and 308 Garand, never had an issue. I've always heard the Lee dies set brass back to very minimum specs. I'll continue to use the forster seater die but not the resizer die.

 

[Dusty Stevens]

Send your fired brass to whidden or tell him which reamer you have. Hes intimately familiar with your chambering. Getting mainstream dies off the shelf is a crapshoot at best. You can get 10 of the same die and one may be perfect but who wants to buy dies more than once?

 

[Lucky Shooter]

Comparison of STD and Small Base Dies

All this discussion got my curiosity up and I did some measurements----just to compare.

I used Starrett Small Hole Gages to compare such dies, Redding 6PPC and 223----since these
were the only SB dies I have. The Small Hole Gages require a good bit of feel to get consistent
measurements and I'm not as skilled at this as I'd like but think a got meaningful results.

The SB dies seem to be about .004" to .006" smaller than the STD dies, just inside the case
mouths. Put this into the hands of a real machinist and you'd probably see slightly different
numbers.

Anybody else want to give this a try ?

A. Weldy

 

[C.E.Smith043]

Comparison of STD and Small Base Dies

All this discussion got my curiosity up and I did some measurements----just to compare.

I used Starrett Small Hole Gages to compare such dies, Redding 6PPC and 223----since these
were the only SB dies I have. The Small Hole Gages require a good bit of feel to get consistent
measurements and I'm not as skilled at this as I'd like but think a got meaningful results.

The SB dies seem to be about .004" to .006" smaller than the STD dies, just inside the case
mouths. Put this into the hands of a real machinist and you'd probably see slightly different
numbers.

Anybody else want to give this a try ?

A. Weldy

Imo, that's alot!!!

 

[Lucky Shooter]

I agree with C.E.Smith043-----it sounds wrong and I don't trust my own measurements on this.

I had a few twice fired 6PPC cases and resized a couple of them----1 in the STD Body Die and 1 in the SB Die.

The SB Die sized the web area approx .002" smaller than the STD die and sized the shoulder diameter approx .001"smaller.

These measurements were much easier for me and I have more confidence in them. Have never thought much about what these differences are but think I now have a better feel for it.

A. Weldy

 

[NV_Dmax]

Comparison of STD and Small Base Dies

All this discussion got my curiosity up and I did some measurements----just to compare.

I used Starrett Small Hole Gages to compare such dies, Redding 6PPC and 223----since these
were the only SB dies I have. The Small Hole Gages require a good bit of feel to get consistent
measurements and I'm not as skilled at this as I'd like but think a got meaningful results.

The SB dies seem to be about .004" to .006" smaller than the STD dies, just inside the case
mouths. Put this into the hands of a real machinist and you'd probably see slightly different
numbers.

Anybody else want to give this a try ?

A. Weldy

.004” should be about right for an off the shelf die.

You’re going to probably get a lot of spring back in the web area; thick and un annealed brass down there. The die I am having made will be appoximately .004” smaller than the Whidden die I have now.

Fired brass, that clicks, from this chamber is .0015” larger than factory BR Lapua brass at the base. I want .0015”-.002” smaller brass so in order to get that I figure .003-.004” worth of sizing.