Another stupidity by yours truly, I was setting my Forster FL 308 Sizing Die to match the chamber of my rifle. Fired Case was 1.629 Datum( 1.572” shoulder) , set the die for 1.627( 1.570 shoulder), was using then Hornady Lube for the 3 sample cases once I got my preferred bump, went to proceed bulk process using my lanolin/ alcohol mix, now the bump went down to 1.620, (1.562”shoulder )that’s .009” difference. I know every rifle chambers differently, but what is the lowest datum measurement you’ve tried or shoulder height., if not mistaken the 308 has shoulder height of 1.560” Resized 200 pcs on this. Thanks
Shortest shoulder or Headspace for 308
- Thread starter ffgats
- Start date
Chambers and dies vary in size, I measured several fired cases with a Hornady cartridge case headspace gauge and set the die for .002 shoulder bump.
The reloading manuals tell you to wipe the lube off the shoulder and neck before sizing. And any excess lube on the case body will be squeesed upward onto the case shoulder. Meaning the amount of lube on the case can influence the amount of shoulder bump as it flows upward.
Study the SAAMI drawing below, there is .010 between min and max headspace. And there is approximately .003 between the GO and NO-GO gauge for setting up a new rifle or barrel. (not on drawing)
Below the chamber headspace can be from 1.630 min to 1.640 max and a new cartridge shoulder location can be from 1.627 to 1.634.
I buy bulk once fired Lake City 7.62 brass for my Savage .308 bolt action rifle. I size the once fired cases using a small base die set for maximum shoulder setback with press cam over. "AFTER" firing these cases in "MY" rifle I then set the die for approximately .002 shoulder bump. I'm not sure what you mean by your case shoulder measurements. BUT the more the case is fired and resized the more spring back the case will have after sizing. And I have never had a resizing die push the case shoulder back .009 shorter than chamber headspace. (if the chamber is within min and max SAAMI headspace)
The reloading manuals tell you to wipe the lube off the shoulder and neck before sizing. And any excess lube on the case body will be squeesed upward onto the case shoulder. Meaning the amount of lube on the case can influence the amount of shoulder bump as it flows upward.
Study the SAAMI drawing below, there is .010 between min and max headspace. And there is approximately .003 between the GO and NO-GO gauge for setting up a new rifle or barrel. (not on drawing)
Below the chamber headspace can be from 1.630 min to 1.640 max and a new cartridge shoulder location can be from 1.627 to 1.634.
I buy bulk once fired Lake City 7.62 brass for my Savage .308 bolt action rifle. I size the once fired cases using a small base die set for maximum shoulder setback with press cam over. "AFTER" firing these cases in "MY" rifle I then set the die for approximately .002 shoulder bump. I'm not sure what you mean by your case shoulder measurements. BUT the more the case is fired and resized the more spring back the case will have after sizing. And I have never had a resizing die push the case shoulder back .009 shorter than chamber headspace. (if the chamber is within min and max SAAMI headspace)
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I've seen it happen with a Dillon die, which apparently is supposed to be set up using a headspace gauge? I've never owned a Dillon .308 die, so I have no idea if this was a standard situation or if the die had been modified.
It was a used die, and didn't come with instructions. I believe the new owner set it up as he had done with other dies, by turning it down until it touched the shell holder.
Anyway, the shoulder was pushed back considerably further than it should have been. IIRC almost 0.030" further back. Enough that an unfired round wouldn't extract because the extractor claw wasn't being pushed over the case rim.
I think he ended up tossing the rest of the cases from that batch, there were a lot less than 200 of them.
I think your question is really, is it safe to load and fire these to move the shoulder back where it should be?
It was a used die, and didn't come with instructions. I believe the new owner set it up as he had done with other dies, by turning it down until it touched the shell holder.
Anyway, the shoulder was pushed back considerably further than it should have been. IIRC almost 0.030" further back. Enough that an unfired round wouldn't extract because the extractor claw wasn't being pushed over the case rim.
I think he ended up tossing the rest of the cases from that batch, there were a lot less than 200 of them.
I think your question is really, is it safe to load and fire these to move the shoulder back where it should be?
Just an update, I decided to use my resized brass that were i would say resized not on my liking. 1.562” base on shoulder, 1.624-1.625 base on the datum, the brass extracted and ejected good, Inspected the cases and no signs of bulge on the cases, remeasured the shoulder and datum and it reads 1.569”, shoulder and 1.629” datum. All gauges were Hornadys headspace bump gauge and Sinclair Bump gauge which index on the shoulder.
