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Posted: 8/22/2017 1:10:59 PM EDT
I just bought a new DPMS G2 .308 Recon and had a question about case ejection.  The gun has performed flawlessly with both brass and steel cased ammo.  When the cases are ejected, some of them are hitting the upper receiver between the case deflector and charging handle, which is denting the case neck and leaving marks on my receiver.  Is this normal with this gun or is it a gassing issue?

Picture of contact areas.  Looks to me like the bottom of the case is hitting the deflector and rolling over it and the neck hitting the receiver.  Brass marks are seen on the front and back of the case deflector.

Picture of dented case necks.
Link Posted: 8/22/2017 3:01:26 PM EDT
That's interesting.  Not saying it can't happen, I've just never encountered it on AR15's or AR10's at that spot.  How is the empty missing the forward assist bump?  Do you have something else attached to the gun near the ejection port or on the top rail outside of the norm?  Are you a lefty shooting a right handed rifle?  Is there something to the ejection port side of your gun that is bouncing the case back toward the gun?...indoor shooting range, barricade, etc.
Link Posted: 8/22/2017 3:20:26 PM EDT
Make sure both ejectors are working and well lubricated.  If the bottom ejector is pushing harder it could cause the case to come out angling above the deflector.  It may also be the gun is running slow but that will resolve itself as the gun breaks in and starts running a bit faster.
Link Posted: 8/22/2017 5:07:31 PM EDT
Added pictures....hopefully that helps.  I don't see any marks in the ejection port itself.
Link Posted: 8/22/2017 5:31:50 PM EDT
My GII didn't do that with the factory gas block installed and it isn't doing it now with the SA adjustable gas block.
Link Posted: 8/22/2017 6:24:45 PM EDT
OP are you sure the impact dings are being caused by both steel and brass ammo?  My only AR that "D's" the neck is my 300BO, but that is pretty common with that caliber.
Link Posted: 8/22/2017 9:04:44 PM EDT
Discussion ForumsJump to Quoted PostQuote History
OP are you sure the impact dings are being caused by both steel and brass ammo?  My only AR that "D's" the neck is my 300BO, but that is pretty common with that caliber.
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It does it with both brass and steel.  I forgot to mention, it only does it on ~1/3 of the cases...
Link Posted: 8/22/2017 9:16:20 PM EDT
My new to me DPMS G2 is doing something like that as well.  I'm playing with an adjustable gas block to see if that improves anything, but there's only so much time.  I also should take everything apart, clean and lube it since I don't know how attentive the previous owner was, but I was too focused on my rail project.

How is the case head? Too much gas leaves nasty swipe marks from the ejectors on my gun.

Edit to fix "auto-correct"
Link Posted: 8/23/2017 9:52:43 AM EDT
It's running a bit on the "slow" side.  If it's functioning reliably, I wouldn't sweat it.  The ejection should move forward as you get a few rounds on the gun.
Link Posted: 8/23/2017 9:52:57 AM EDT
Definitely a slow gun.  As long as its not malfunctioning I would not worry about it.  The slow bolt is letting the case rotate further before it hits the shell deflector and its rotating around the shell deflector and hitting the side of the receiver.  It will go away as the rifle breaks in and starts running faster.
Link Posted: 8/23/2017 10:29:32 AM EDT
Very common on the G2.

Don't shoot it from your left shoulder as you will get hit in the cheek.

DPMS has extended the shell deflector on the newest G2 and that design should migrate to all models.

The G2 dual ejectors really push the fired case out early for reliability and the design needed more shell defector.
Link Posted: 8/23/2017 11:23:04 AM EDT
Thanks for everyone's input, I'll keep shooting it and see if it gets better.  How may rounds do you estimate it will take to break the gun in?  I have about 60 rounds through it so far.
Link Posted: 8/23/2017 12:06:38 PM EDT
Not quite the same issue, but because I was unable to find my brass shooting out in the woods, I bought one of these (the A3 version of course): http://www.brownells.com/shooting-accessories/range-gear/shell-catchers-deflectors/brass-deflector-prod18554.aspx

I'm sure it would solve the symptom of your problem. Actually pretty easy to butcher it to fit other accessories on the rail, since as it comes it takes up a fair bit of rail space.
Link Posted: 8/23/2017 1:12:36 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted 

DPMS has extended the shell deflector on the newest G2 and that design should migrate to all models.
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You mean the g2 has a gen 2?
Link Posted: 8/23/2017 1:32:54 PM EDT
They've made a fair number of running changes. Would be nice to know if they were all done as of XXXXX serial number, or if there is no way to know other than to inspect every component.
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