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Reloading Podcast 404 – page not found, please consult the manual

Hello, and welcome to the Reloading Podcast here on the Firearms Radio Network.  

Tonight the gang is answering more questions. 

Thanks for the great information in episode 388, give it a bump. I knew bumping the shoulder was an important part of reloading bottle neck cartridges, but didn’t fully understand what it meant or how to check it. I currently full-length size because I load for a .308 AR.

I have about 200 Federal cases I cleaned, sized, annealed and trimmed a few months ago. I have always followed the die maker’s directions, screw it down until it touches the shell holder, then give it another quarter turn and tighten the lock nut. These always drop right into my case gauge. Are they on the minimum spec side? Yes, but that’s always been my method to reload for a semi-auto to get consistent cycling.

I’m ready to start reloading these, but of course now I’m curious, how much did this push the shoulder back? So I got the Hornady Headspace Comparator kit. To my amazement I had pushed the shoulder all the way back from 1.1632 to 1.619, 13 thousandths compared to a fired case! (same Federal case) 

  • So naturally I have some questions:
  • Are these safe to load and fire?
  • If I load and shoot them, will they stretch at the case head, leading to a separation?
  • Being too short, could the case head slam into the bolt causing damage when fired?
  • How much will this affect accuracy?

If it weren’t for the cost and scarcity of primers right now, I guess I could fire-form them. Now I’m really curious and a little concerned, so I got a Sinclair 20 degree bump gauge insert for .308 that Paul recommended. My fired cases measured 1.580 and my sized cases measured 1.562, a full 18 thousandths shorter!

These numbers are quite different from the Hornady set, but those measure off the datum, so I’m guessing the Sinclair gauge measures off the shoulder? If that’s so, my shoulder measurement (1.562) is two thousandths longer than the SAAMI spec, which is listed in my reloading manual as 1.560 – wouldn’t that make it in spec, even though it is 18 thousandths shorter than a fired case?

Just to clarify, when the cartridge chambers, does the cartridge rest on the datum or the shoulder? Both the Hornady and Sinclair measurements indicate I bumped my cases back way too far compared to my fired cases, but if the shoulder measurement is correct, I should be fine to fire these, correct?

Finally, I have a few boxes of Federal Gold Medal .308 loaded with 168 MatchKings, they measure 1.620 with the Hornady set, only 1 thousandths longer than where I pushed my case necks back using the directions with my FL sizing die (1.619).

Thanks for your feedback, long question, but I am sure there are a lot of reloaders do what I have and simply follow the manufacturers directions for setting up the dies and not truly understanding how much they are pushing back the shoulder.

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