Six sows down.

[Ratdog68]

Am I understanding correctly? The gun MAY even fail to extract with manual cycling of the bolt... and with it locked back, needs a gentle mortaring to jar the fired casing from the chamber? But, this gun will run fine w/o issue for long periods?

Are marks present on the brass? Does the chamber need polishing?

Does it do it with only one brass headstamping? Hornady uses more than one headstamping, reportedly, each one is a different brass manufacturer. If I recall, factory loads have a different headstamp than do the "for sale as component" brass. Could it be a variance of dimension of brass between headstampings? All makes of brass are not created equally. Composition, thickness, etc.

 

[DaveABQ]

Originally had an issue with weak extractor spring and buffer, replaced with new in the Superbolt. Yup, came from H with a weak spring.

The extractor would just jump over the case rim when trying to extract, even with manual cycling. Firing a gun with a weak extractor spring can extract/eject the case.

Chamber is polished, but not over polished. If you over polish a chamber, You can cause early unlock as there needs to be some resistance. Flitz was used with a felt pad, as I do on all my builds.

Believe it is only Hornady brass, Todd can answer that, interesting point, but even them, same lot, didn't do it last week and did it this week.

I just need to look it over, as I'm really baffled at this point. I've built over 100 AR's for people, and probably half of them are 6.8's, as I recommend them to many people. I believe I can find the problem quickly if I fire it, look at the brass, pull it all apart, see what is happening.

The barrel is bedded, however it has a standard gas block. I want to put on an adjustable, and I am going to bed the gas block to make sure no gas is escaping at the block.

Supposedly no marks on the brass, no marks on the rim from the extractor claw. But something is going on. Overpressure and cause the brass to stay chambered and the extractor to jump the rim, however you will see the rim torn up, which apparently isn't the case.

Right now the issue appears to be a weak extractor spring and/or spring buffer, but I've run so many thousands of rounds through my guns and never changed them.

Too much gas and burnt powder because of use of the suppressor can cause a dirty chamber, and if there are still some abnormalities in the chamber, can cause it to unlock late or failure to extract, but again, if this occurs you get marks on the rim.

So only way for me to diagnose is to shoot with different ammo, with and without suppressor, diagnose, completely disassemble, put back together, verify headspace again, verify the receiver is square (I squared it when I built it), install and adjustable gas block, bed the gas block, install new extractor as well as new spring and buffer, and shoot the **** out of it.

 

[gshock]

It fails to extract sometimes I've tried two separate bolts now and it still does it. It will work fine for a while then it does it again. This was factory 120sst 's and the brass came out easy it just fails to grab sometimes.

I had similar issues when I installed a suppressor and adjustable gas block on my arp6.8 with sst 120's. Sometimes it jammed and sometimes I could empty a whole mag. Problem seem to disappear when I swapped out the buffer and spring with the spikes buffer and spring.

Sounds like a decent hunt none the less.