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View Full Version : DIY upper, XM193, nasty pressure signs


Disciple
08-20-20, 18:17
I fired a new upper today, the first one that I have assembled myself, using a new case of XM193 from storage. I would have preferred not to try a new barrel with a new case of ammunition but it's the situation I created for myself. I fired only two rounds, and I am glad I used a stick to pull the trigger as the second case had an extremely flattened primer. The cases are also bulged.

I used a 16" Faxon pencil barrel. The old reviews were good and I missed the comments about declining QC before ordering. The bolt would not close on a Forster 223 Rem field gauge but XM193 chambered easily.

I know there have been problems with XM193 itself, so should I try weaker ammunition (e.g. .223 Wolf WPA) or should I not fire this again until I can have it inspected?

https://i.imgur.com/cdpxtxr.jpg
https://i.imgur.com/thcplIq.jpg
https://i.imgur.com/EtOWXue.jpg
https://i.imgur.com/42nOnWQ.jpg
sinister
08-20-20, 18:26
Holy crap, that's ugly.

Looks like a blind drunk guy used a worn-out chamber reamer at 1530 on a Thursday afternoon payday before a four-day weekend with the hooker convention in town.
Clint
08-20-20, 18:32
Most likely a chamber issue.
Disciple
08-20-20, 18:44
Holy crap, that's ugly.

No need for inspection then; these photos alone should be sufficient for Faxon to RMA the barrel?
Disciple
08-20-20, 18:46
Most likely a chamber issue.

I thought understatement was a lost art. :)
ColtSeavers
08-20-20, 18:49
Send that barrel back.

Damn shame Nathan left Faxon.
Disciple
08-20-20, 18:54
Damn shame I didn't read about that etc. until after I bought this barrel. Thanks.
ColtSeavers
08-20-20, 18:57
Damn shame I didn't read about that etc. until after I bought this barrel. Thanks.

Sorry, wasn't trying to rub salt in the wound.
Disciple
08-20-20, 19:01
I did not think you were. :)
MistWolf
08-20-20, 19:36
Most likely a chamber issue.

Agreed. That's not over pressure, that's an over sized chamber diameter.
TomMcC
08-20-20, 19:54
The primer on the left doesn't really look that bad, the one on the right is a bit flatten. If you were dealing with high pressures you'd probably see a pretty good indentation left by the ejector. You'd see some brass flow into the ejector. I don't see anything. Primers aren't a super reliable way to tell pressure issues. Looks like your chamber is some thousandths over near the base of the cartridge.