Fireforming to bring Cases back into Spec

[Oso]

During an OCD moment, my brother loaded 1,000 rounds of .223. These were nice components...new Lake City brass, VMax bullets, CCI primers, and H335 powder. Ignoring the fact that he didn't trim the case length, he used a neck die that was set too low resulting in the shoulder getting pushed back by 1/32" - 1/16". The end result is that with the streched out neck and low shoulder these rounds are jamming my AR as the force of the bolt slamming closed creates a bulge along the incline of the shoulder. After 5 rounds I found myself using a rod and hammer to apply pressure against slide while second person pulled on charging handle for all their worth...

I plan to sort through the entire batch with a Case Gage to identify cartridges that might be an issue. My thought is to shoot these "problem" rounds through my bolt gun to fireform the case back to standard dimensions. My concern is that these rounds are at full powder loads. I am prepared to pull bullets and dump powder.

What is the recommended powder percentage (reduced load) for safely performing fireforming?

Thanks

 

[Oso]

Brand new Daniel Defense...didn't want to beat it up quite yet by a hard slam. It wasn't the crimp. Initially believed it was a fired round that jammed. After initial attempts with charging handle went ahead and took off the upper to get a better view of bolt. Used a cleaning rod to gently push the case while pulling on the charging handle...slight movement inside the barrel as the bullet was pushed back into the case. TUrned gun over and carefully let powder trickle out of barrel. Hence, I don't think it was the crimp.

As to the dies...I don't know what he was using or doing....really wish he wouldn't have. If he were using case length resizing die I can't understand how the shoulder could have been pushed backwards. THe only other idea is that the case was long and with the force of slide closing the lip made contact without the shoulder of cartridge being seated into the chamber. The result being that the shoulder bulged outward to relieve the pressure on the cse. Perhaps this is how/why the shoulder appears to be pushed back. Some time with the Case Gage this evening should give me an answer.

I am a little

 

[BC 6.8]

If you had to push the bullet out of the barrel of a load that didn't fire, you have one of two problems: the COAL of the cartridges is too long and the bullet got stuck in the rifling (SAAMI spec for ARs is 2.26 COAL), or there is not enough neck tension on the bullet and when the round is chambered the bullet slides out of the case (need to check what kind of die was used and what size bushing). Another thing is it is a bad idea to try to neck size only for an AR even though it is new brass.

New brass should not need to be trimmed since it is NEW. I would recommend investing in some full length resizing dies and a way to measure to the shoulder of the case like the Hornady headspace kit.

 

[ksthomas]

I'm heading out the door to St. Louis for our State Service Rifle Championships, but clearly, we need to chat a bit. Be back on line Monday, and we can try to help you sort this out.