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 DPMS LR308 beating itself to death?
Truegrave  [Team Member]
1/13/2012 1:34:34 PM EST
I've had this DPMS Oracle for just under a year with roughly 1000 rounds fired. I've already had to replace an extractor, and now I am beginning to notice a lot of unusual wear. It looks like a groove is being carved into the upper receiver by the bolt cam pin. In addition, there are palpable lines in the cam caused by the bolt carrier. The cam is also showing heavy wear near the head. Is this something that is normal for civilian guns or should I be calling DPMS?

Pictures of upper by the gas tube.

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turb06le240  [Member]
1/13/2012 1:56:00 PM EST
I cant really tell from the pics, but DPMS has decent cs, I would call them and send them pics...
Gatorhunt  [Team Member]
1/13/2012 1:58:10 PM EST
It's semi normal to have wear there, I have a rifle that has 4-500 rounds on it and shows hardly any wear there and another with about 300 on it that shows noticeable wear there.


That said, yours does look a little deep, what does the cam pin head look like?
Truegrave  [Team Member]
1/13/2012 2:45:34 PM EST
Here is the cam pin. The red area is the uneven wear that I was talking about. The blue area points to the ridge that is being created by the bolt carrier. The marks are mirrored on the other side of the pin as well. The head doesn't look bad at all. There is still just a little bit of blue-ing left on the pin's edges- nothing out of the ordinary.


Gatorhunt  [Team Member]
1/13/2012 3:16:31 PM EST
Actually I think the blue part is being created by a sharp edge on the bolt channel not the carrier, the red area is from the carrier (I think), or maybe the upper.


Seems a little excessive to me, I would contact DPMS and show them the pictures.
Dano523  [Moderator]
1/14/2012 6:04:30 AM EST
Truegrave, Your slow close to the problem, that if it had been a snake, it would have bit you.

Bottom of the cam bolt in the carrier was peened a tad too deep upwards, and the cam bolt is not going down the hair more that it needs to into the carrier channel for it.

The blue marks on the cam is normal, but should be a hair more upwards. On the Red marks, kind of normal for wear, but it the end of top flats on the key where the finish if gone that is making contract to the upper. And regarding this wear, kind of normal as well as the cam has it way with the upper bearing track as everything mates in (read DPMS could have milled the channels a tad wider, but still going to come back to the slot in the cam slot, cam in the upper, and even bolt to the carrier all leading to the everything moving around during lock/unlock that you going to see a bit of wear to the area.

But I will give the rig a huge thumbs up on the cam to upper slot wear overall, since I have seen some rigs at 1K rounds that have a tight upper track to cam pin (that the cam has had to have it way with the upper slot to self polish out), and the cam has removed all the anodizing from the upper track side walls during break in.

Bottom line, all not that bad, and now that the upper has self mated in, the worst of such is in the past (fouling from such during break in that you would need to run the upper heaver CLP lubed until this point).
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