AR Sponsor
Posted: 7/19/2009 7:45:38 AM EDT
|
A while back I posted problems I was having with my LR-308B. DPMS said I had a mag problem. Sent the mags back and got the new ones in. I had them substitute one 19 round mag for a 10 round mag as I shoot off the bench. First test. The 19 round mag jams with 3 rounds left in it, just like the others. The 10 rounder wouldn't pick up the last 2 rounds. On further investigation, it seems the back of the rounds are not coming into position for the bolt to pick them up. On the 19 rounder, they come up enough where the bolt hits the body and drags them forward and then rides over the shell. It shoves the shell forward and then jams. The 10 rounder wouldn't let the shell come up enough for the bolt to even catch it. Here is a pic of one shell in the mag: Jam Click on the pic to make it bigger, then click on original at the top to blow that up. I worked with both mags in the house. Shoved the followers up and down and put a little CLP on the back of the plastic followers. In the house, both mags seemed to work just fine when I hand cycled the gun. Outside for the test, the 10 rounder worked great. The 19 rounder never changed. Still jamming. My question is, do I give DPMS another chance to replace this mag? Or are DPMS mags too spotty to trust? I've wasted a LOT of ammo testing these mags. Or is there a better mag out there?
|
|
Looking @ the photos in the link I would say it is not the mag but an issue with the bolt not traveling far enough back to properly chamber a round. The other pic is of a double feed? Is the top round expended or a live round?
Because it is not every round therefore not consistent we need some additional info: - ammo used? - tried switching ammo? - reloads? - mods to the gun or straight out of the box? - were you using the brass catcher @ the time of each failure? |
|
The one photo of the double feed is when the gun was brand new. That issue is gone. The gun is not short stroking. Ammo used so far is Winchester 150gr power points, LOS MEN surplus and OFV surplus. Gun behaves the same with all ammo. I have a DPMS mag I borrowed from a friend. He hasn't even shot his gun. That mag is flawless in my gun. No problems whatsoever. That mag is what made DPMS conclude I had a mag problem. His mag still works flawless in my gun. When you hand cycle the gun, you can see the bolt shoving down on the shell as it comes back. The back is staying down. When the bolt goes forward, the bolt can't pick the shell up or the bolt hits the body of the shell and drags it out of the mag. Causing a jam. So this is the third 19 round mag from DPMS that won't work. I'm wasting a lot of ammo on this mag problem. At least when the 10 rounder was messing up, it didn't mangle the brass. I have twelve 10 round bags of reloads set up to test for accuracy. I don't want to use them until the gun runs. Mangled brass and bullet setback from jams ain't a good way to test them.
|
|
Take the mags apart and trim the plastic flash off the followers with a sharp knife. Rub the inside of the mag body with 0000 steel wool to eliminate the roughness of the finish. If you find any burrs on the inside of the mag body, knock them down with a small file or fine sandpaper. Reassemble mags and retest.
Also, what is the overall length of the cartridges you are shooting? |
|
Quoted:
Take the mags apart and trim the plastic flash off the followers with a sharp knife. Rub the inside of the mag body with 0000 steel wool to eliminate the roughness of the finish. If you find any burrs on the inside of the mag body, knock them down with a small file or fine sandpaper. Reassemble mags and retest. My thoughts exactly. Sounds like the followers are getting hung up somehow. Strange that it's happening in several mags though. |
AR Sponsor