AR 10 DPMS feeding issues

[Gregg C]

Howdy, all. I finally bit the Bullitt, and got myself an AR. It's an 80%, built by a friend of mine. Near as I can tell, he did a good job. Let's assume he knows what he is doing.
The issue is, it jams. I know NOTHING about gas guns, so I want to tinker with this thing, fix the problem, and in the process, learn something.
On another thread, lots of GOOD information was given. Not my thread, so here we go...
So far, I have polished the feed ramp. Seemed to help some, but I did not document failures previously, so I don't really know. What I DID learn was it's from the right hand column in the magazine that these "jams" occur. Some of the guys in that thread suggested adjusting the mag lips up a touch to allow the cartridge to stick up into the bolt path more. Having decided to try that next, I noticed the back end of my mag wraps around the case head. Seems to me that if I just bend the lips up, only the shoulder will come up, and I want the entire shell to come up. Am I right? So that means I need to cut the back of the mag , to free up the whole feed lip. Am I all funkered up here ?

 

[Gregg C]

This is what the rifle is doing...

 

[Deleted member 115360]

Get a different magazine and see if the magazine is the issue before you bend it all out of whack.

 

[Deleted member 115360]

I doubt it's causing that.

 

[Gregg C]

Well, this is the second mag. The one it came with did the same thing.

 

[Deleted member 115360]

Not the mag then.

Do you have a fixed or adjustable gas block?

 

[Deleted member 115360]

I run a new ar dripping with oil. It takes some cycling to get everything smooth, and oil helps. Also what kind of recoil system does it have, a buffer spring or a silent capture?

 

[Gregg C]

Fixed gas block, and dang, there you go, talking about something I don't know!! I THINK it's a buffer spring.

 

[Gregg C]

I just googled it. Definitely not silent capture.

Seemed plenty wet with oil,....

 

[ARlife4me]

I'm a gas gun guy so I'll need more info on gun. Cartridge, barrel length, gas system length, gas port size, bcg type, buffer weight and style and ammo used (brand and type).

 

[ARlife4me]

Also, what gas block is being used (adjustable or not) and brand of gb.

 

[SPitty]

There was another post here recently with an AR feed issue. The shell was nose diving because the front of the shell was not sitting up high enough in the mag. Opening the feed lips a hair (front only) resolved his issue. You do not have to do anything to the back of the mag. As long as the bolt can pick the shell up, it will be fine. From your picture the back of the shell is in a good position. It would have been nice to see how a complete round looks in the mag, but it probably has a nose down cant which is not good.

 

[ARlife4me]

As far as upper assembly goes, was it a complete build or built?

 

[Gregg C]

I'm a gas gun guy so I'll need more info on gun. Cartridge, barrel length, gas system length, gas port size, bcg type, buffer weight and style and ammo used (brand and type).

308 Win, 22 in barrel, rifle length gas sys? Gas port size unknown, can measure it, would the buffer have any I.d. on it? Fixed gas port, unknown maker. I believe the upper was complete, from DPMS. An 80%, so a build?