DMPS G2 AR10

[Stu_Padaso]

I bought this rifle for a good price , I'm somewhat new to AR's let alone AR 10's any way
Rifle was brand new went to range , first five shots were perfect , jammed every shot after
All FTF , GOLD match ammo Federal oiled
any Ideas Sending it back is not a option.

Thanks Stu

[buffalobo]

Post some pics. You will soon have many suggestions as to issue and possible corrections.

[KS63]

Why is sending it to DMPS for repair not an option?

[Stu_Padaso]

Why is sending it to DMPS for repair not an option?

Because im hoping its something easily fixed , im thinkin it was ammo ! ill let you know

[saltydecimator]

how much you pay?!

[Stu_Padaso]

how much you pay?!

$1100.00 too much ?

[Grant H.]

Foxtrot is right, DPMS chambers are pretty tight when new. Try using some Winchester White box, or something similar. Basic, reliable, and good blasting ammo. Run 100 rds or so, and then clean it really well.

One of my DPMS barrels had a very thin layer of thick, hard grease (think grease packing a gun for storage) in the chamber and needed to be cleaned out. A good chamber brush makes this much simpler. I actually used my .308 chamber reamer to remove the bulk of it, and then scrubbed it out with the chamber brush and hoppes 9. This rifle was worse than you experienced, because it wouldn't fully go into battery, but it could be similar.

Did the brass have any scratches or marks in the outside? Brass is great for showing these issues.

$1100 sounds pretty fair for a NIB DPMS LR308.

[Stu_Padaso]

7580875809

every cartridge that failed looks like this Mdl# LR-GII , for the 5 rds that i got off , it was a rush i love the weapon.

appreciate the advice 4-sure!

[bellavite1]

It kind of looks like a double feed...
I hate to state the obvious, but have you tried different mags?

[Stu_Padaso]

Now when i bought the mag they asked me what type ?? of Ar10 mag , how many diff ones are there ?
I stopped him at Stoner , its a brand new magpul

[Hoser]

You can spend a lot of time and money trying to figure this out. Life is too short.

Send it back to the mother ship.

[bellavite1]

Now when i bought the mag they asked me what type ?? of Ar10 mag , how many diff ones are there ?
I stopped him at Stoner , its a brand new magpul

Magpul should be ok, I believe, for DPMS, but you may want to try a proven mag from a friend.
Alternatively it could be short stroking.
How is ejection if you try to single load the mag?

[DireWolf]

Assuming sending it back just isn't in the cards, 3 possible issues come to mind for troubleshooting:

1. Mag release button not screwed on far enough. This can cause a loose mag seating and cause the bolt to skip over the case head and grab forward on the case with the bolt lugs. Looks exactly like mark in pic when this happens.

2. Way over-gassed combined with either weak mag-springs or too much friction at feed ramp (can't really tell how smooth FR is from attached pic). What buffer weight does it have currently? Possible that too much gas-to-mass or too heavy buffer-spring may have the BCG cycling too quickly for the mag to raise the next round (e.g. if weak spring). May also potentially involve surface issues/debris on feed ramp, and the bolt lugs are skipping over the case head due to some impedence, and biting in further forward as the case moves up into-plane. Look to see if the case heads are getting chewed up...Possible tests would be new/alternate mag, increasing reciprocal mass, replacing buffer spring, and if necessary giving the ramps a bit of polish...

3. Debris in the buffer tube (or related) area which may be limiting rearward travel of the carrier. Does the carrier have full range of motion and are the spent cases ejecting?

ETA: If it either doesn't (or barely) eject a spent round, maybe it is in fact just short-stroking...can check the gas tube/block/key for possible issues or mosalignment, or possible bent firing pin restricting or seizing up travel of the bolt/cam in the carrier.

[Stu_Padaso]

Assuming sending it back just isn't in the cards, 3 possible issues come to mind for troubleshooting:

1. Mag release button not screwed on far enough. This can cause a loose mag seating and cause the bolt to skip over the case head and grab forward on the case with the bolt lugs. Looks exactly like mark in pic when this happens.

2. Way over-gassed combined with either weak mag-springs or too much friction at feed ramp (can't really tell how smooth FR is from attached pic). What buffer weight does it have currently? Possible that too much gas-to-mass or too heavy buffer-spring may have the BCG cycling too quickly for the mag to raise the next round (e.g. if weak spring). May also potentially involve surface issues/debris on feed ramp, and the bolt lugs are skipping over the case head due to some impedence, and biting in further forward as the case moves up into-plane. Look to see if the case heads are getting chewed up...Possible tests would be new/alternate mag, increasing reciprocal mass, replacing buffer spring, and if necessary giving the ramps a bit of polish...

3. Debris in the buffer tube (or related) area which may be limiting rearward travel of the carrier. Does the carrier have full range of motion and are the spent cases ejecting?

ETA: If it either doesn't (or barely) eject a spent round, maybe it is in fact just short-stroking...can check the gas tube/block/key for possible issues or mosalignment, or possible bent firing pin restricting or seizing up travel of the bolt/cam in the carrier.

Leaning towards feed ramp having burrs on it , it was pretty rough so i took some 2000 grt and smoothed it out, dry cycle is much better going to test this week.
if it fails i think i'll just send it back to DMPS after all.
once again thanks for everybody's help.

[Stu_Padaso]

Stu Padaso

[Stu_Padaso]

ok well took the LR-GII to the Range to day for round two , and im happy to report it shot flawless
not even one hick up , it was a good time. THANKS EVERYBODY FOR ADVISE , change of Ammo
and feed ramp polish seemed to do the trick

Stu

[Ace777]

In my experience most likely a gas issue or buffer tube issue. If the buffers too light it moves to quickly and can cause a sort of double feed, which could explain your casing being bent. Same issue could occur based on the gas tube. And adjustable gas block may be your best option

[<MADDOG>]

You can spend a lot of time and money trying to figure this out. Life is too short.

Send it back to the mother ship.

+1