That is exactly what the cases looked like AFTER full length sizing. Sometimes with no pressure signs..? I even checked once fired at the .200 line and had no "unusual " dimensions. As far as gas settings, it was as the normal "til the bolt locks back" and a 3:00 ejection pattern. Im just glad that I found the 243 lbc....I don't miss the 6 arc.....rsbhunter
Help diagnosing 6mm arc brass
- Thread starter rookie7
- Start date
In case there is any doubt...take a set of calipers and use the stem to measure how far from case mouth to bottom of case inside. Subtract that depth from the oal of the brass case. That tells you where the solid portion of the case stops. Anything more than that should not be left un supported. A random case I just used measured 1.507 oal and 1.351 from case mouth to bottom inside. So, 1.507-1.351=.156 to see where the brass is no longer solid and only a few thou thickness stands between you and 60,000psi. Now..set your calipers to .156 to visualize this and measure from cartridge base to the top of that bulge/belt and reply with that measurement.
I was getting something similar on my 22ARC
Fairly confident I’m not over pressure as speeds and primer pockets are reasonable
I checked all the pertinent measurements of die, chamber and brass expansion and sizing and they are reasonable
In my case it was trashy finish in my Hornandy die.
I put it in the lathe and polished it it up and all is good now
Also rigged up a 5C collet with a stop and locating pin for the neck and clean up the ridge on cases in the lathe.
It’s running really well now
Running well now and really enjoying shooting it.
Fairly confident I’m not over pressure as speeds and primer pockets are reasonable
I checked all the pertinent measurements of die, chamber and brass expansion and sizing and they are reasonable
In my case it was trashy finish in my Hornandy die.
I put it in the lathe and polished it it up and all is good now
Also rigged up a 5C collet with a stop and locating pin for the neck and clean up the ridge on cases in the lathe.
It’s running really well now
Running well now and really enjoying shooting it.
Attachments
Have not read all the posts, but this is why I got rid of my 6arc ar upper. Me and a friend built ar 6 arc's, he built 2, with different mfg's barrels...our brass after resizing, looked like a 7 mag belted case!!! And factory ammo, yes, black and match showed over pressure..to the point of pushing out primers...we both build ar's, so yes, we had top$$ bolts, + length gas systems and matched buffer springs/ weights...I know guys that have smooth running guns now (this was 3-4years ago) . Now, I do have a 22 arc ar that I am totally happy with.... but it has a $700 barrel and top shelf componets....rsbhunter
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