Overcharged?

[PowPow]

http://www.primalrights.com/articles/understanding-pressure

Read this maybe you'll find your answer.

That's a great read. Thanks for posting the link!

 

[Mike3888]

That's a great read. Thanks for posting the link!

Both you and OP are welcome,

 

[Doco Overboard]

I was just going through some once fired brass that belongs to my sons Ar 308 and I seen the same thing with factory ammo just not to the same extant. So, I went and looked at some once fired from my 223 Ar and seen the same once again, so could it be the ejector plunger or something behind it that's gumming up the works? Is it the timing of the rifle? IDK it will be interesting to find out what the resolution is. That was a great article to read and the farther I went the more I thought I would see something written about measuring the case head with a micrometer to determine pressure but I admittedly did not study it thoroughly so I may have missed it.

 

[Mike3888]

Hey Doc.. U mentioned timing. Which goes back to my post #10. Me thinks over gassed. I'm no smith but I've been through this. Sure hope he gets it resolved.

 

[DarrellA]

I'm starting with the easiest stuff first - the gun maybe over lubricated. I did the "dip the bolt carrier & charging handle in a Mason jar of Mobil 1" routine.

I've heard that ARs need to run wet, and boy, was she wet! So I've cleaned everything, including the chamber as best I can. Next time I can get to the range I'll see what we get.

Hopefully this will do it. I have noticed that not all the brass is beat up. Which makes me wonder if the first rounds of the day are OK but as the oil migrates and gets transferred into the chamber I start getting problems. I dunno, but it's worth a try.

And, I'll be picking up a high power magnifying glass to get a better look at my damaged brass.

 

[Doco Overboard]

This is interesting to me Im going to get my AR out and have a look. I never worked on them with the exception of maintenance and some spring tuning I just got one to get a good score and kind of fell out of it. I think I have another to around here to look at too for comparison that has a 556 chamber and the sons 308. That one has a generous chamber and he shoots some Nato ammo in it with no problems but the barrel is stamped 308 Winchester.

 

[DarrellA]

Replacing the standard gas block with a JP Enterprises adjustable gas block seems to have addressed the issue for the most part. I'm still getting swipes on a few cases, but I'm not sure which cases were which as I was tuning the block to find the sweet spot.

The gun was clearly over gassed. Ejected brass is now falling at around 4:00 o'clock instead of around 1:30.

I'm declaring victory and going home.

 

[Mike3888]

Replacing the standard gas block with a JP Enterprises adjustable gas block seems to have addressed the issue for the most part. I'm still getting swipes on a few cases, but I'm not sure which cases were which as I was tuning the block to find the sweet spot.

The gun was clearly over gassed. Ejected brass is now falling at around 4:00 o'clock instead of around 1:30.

I'm declaring victory and going home.

Glad it worked out for ya,

 

[PowPow]

That's a big improvement!

 

[outrider58]

Nice work Darrell.