Looks like extractor upgrade solve AR problem...
by rob 
, Friday, July 10, 2015, 16:57 (3428 days ago)
Every load extracted, ejected and fed perfectly with the same mag changing only the extractor spring and o'ring. Is it common on AR's to throw up burrs like this on the brass? ![[image]](images/uploaded/2015071021551855a03f46a68f8.jpg)
I know all semi autos mark the brass to some extent but just want to be sure this is normal. This is common on my brass before and after extractor spring replacement.
try one with the brass in focus (yeah I know it ain't easy)
by Miles 
, CIVITATES AMERICAE, Friday, July 10, 2015, 17:13 (3428 days ago) @ rob
kinda fuzzy to really tell for sure, but ARs weren't designed to be easy on brass anyway.
As long as it works..........
Two more...
by rob , Friday, July 10, 2015, 18:56 (3428 days ago) @ Miles
Not the best either but a little better angle. Considering the design of the rifle I figure it probably isn't much to worry about.
![[image]](images/uploaded/2015071023552955a05b718dd79.jpg)
![[image]](images/uploaded/2015071023555455a05b8a3bb21.jpg)
that is not common
by bj , Friday, July 10, 2015, 19:45 (3428 days ago) @ rob
It looks like those cases are not wanting to come out of the chamber and the extractor is pulling on them very hard.
Try some with your old load of H335 and some of the factory rounds you were using before, and see how the marks on the brass compare.
I does it occasionally on every load, before and...
by rob , Friday, July 10, 2015, 19:49 (3428 days ago) @ bj
after the extractor up grade. But not the majority of cases...maybe 1 out of 7 or 10.
I agree, but he's got a extractor that's "out there"
by Miles , CIVITATES AMERICAE, Friday, July 10, 2015, 21:36 (3428 days ago) @ bj
From that later pix, the extractor has really got a strong grip on the case.
I'm kind of 'iffy' on the idea that it's taking such a strong extractor engagement to make your riffle work with that load. A 16" barrel shouldn't need that.
The primer's not showing any pressure indicators, but something isn't just 'right'.
I wonder if polishing the chamber would help...NM
by rob , Friday, July 10, 2015, 22:11 (3428 days ago) @ Miles
.
couldn't hurt!
by Rob Leahy , Prescott, Arizona, Saturday, July 11, 2015, 12:31 (3427 days ago) @ rob
--
Of the Troops & For the Troops
Might not hurt to try it.
by Miles , CIVITATES AMERICAE, Saturday, July 11, 2015, 16:00 (3427 days ago) @ rob
I've not had these kind of troubles, but the only AR we have that's ever been handloaded for is Dad's A4 clone and he doesn't use .mil brass for handloading.
Does yours have a chrome-lined chamber?
Those are slick enough that I would *think* that wouldn't be a problem. Of course it doesn't hurt that the GI brass made for those weapons run harder than Remington's stuff usually does...
Nope, not chromed lined...
by rob , Saturday, July 11, 2015, 17:08 (3427 days ago) @ mcassill
It's an Eagle Arms upper by Armalite. Same as a regular Armalite Armalite but without a chrome lined bore...which supposedly tends to be more accurate than the chrome but I don't know. This one is a sub inch gun with several factory loads and my handloads but I'm sure having a hard time trusting it after this happened. Makes me want a Mini-14 again.
My suspicion is that...
the change in brass (to Remington) hiked pressures enough to push a weapon that was already somewhat overgassed over the edge to where it had extraction problems. In this case it isn't chamber pressure that's the important detail so much as pressure at the gas block. As Miles has suggested, a heavier buffer may help. An adjustable gas block might as well. Or you can stick to loads that the rifle demonstrates that it likes.
I kind of agree...
by rob , Saturday, July 11, 2015, 20:11 (3427 days ago) @ mcassill
I think it's trying to extract before the pressure drops enough in the barrel to let the brass fully contract (or at least contract to an extractable size) or the chamber is a bit rough making the extractor work harder than it should to get the brass out...the extractor alone should not be the sole extraction force on the case. I think I'm gonna polish the extractor and see if that helps (one thing at a time) and then try a heavier buffer. That should delay the unlocking of bolt slightly giving the barrel gas pressures time to subside. I'm not gonna get crazy on the chamber polishing either...just some JB Bore paste or Flitz on a chamber mop and a drill to remove any surface roughness. Ultimately, I'm gonna build an entirely new upper for this rifle (lower) using an 18" mid length gas system with probably a Wilson stainless fluted .223 Wylde chambered barrel...but that's just current speculating.