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geetarman
October 20, 2012, 08:07 AM
I went to the range yesterday with a DPMS LR-308 and 4 magazines.

I also had my log book.

All four magazines are loaded with 10 rounds and are numbered.

I had a failure to feed at round number 6 in magazine 1 and when I went to log it in my book, I noticed that magazine 1 has had a failure at round 6 everytime it has been used.

Now that I know it is magazine related, I would like some info in what I should be looking for to fix the issue. I also have one other magazine that has the same issue at the same place.

Should I be looking for flash on the follower? Burr on the inside of the magazine?

I am guessing whatever the problem is, it is a very small deviation from design but I am not sure what to look for.

I don't know how I would check for resistance just by pushing down on the follower. I don't know how I would keep from applying uneven pressure to the follower that might hide the problem.

One of the ROs suggested taking the mag apart and spraying the inside with pure silicone. I have never heard of this.

Any ideas?

ripnbst
October 20, 2012, 08:35 AM
Spraying with silicone lube might work but silicone lube is sticky so they will get dirty fast. Flash of follower isnt likely the problem as it would be constant on all rounds. A slight burr or dent or ding in the mag at a certain location that happens to be where Round 6 feeds is more likely. I would definitely take it apart, clean and inspect. Never a bad thing.

Mags are not that expensive, you could just buy another one.

HiBC
October 21, 2012, 03:36 AM
FWIW,the 10 rd mag that came with my LR308L malfunctioned from the start.I had ordered some C-Products mags before the rifle was delivered.They work fine.

I do not think the lips were quite right on the original mag.

lmccrock
October 21, 2012, 09:03 AM
Are these 10-rd mags? Or factory 19? Or the new factory 20? DPMS had a bad batch of factory 19-rd mags a few years ago. They were VERY good about replacing the mags.

That said, have you taken them apart and inspected the insides? There may be an internal defect.

Not sure about long term use of silicone due to the need to keep them clean, but sounds like a good debug tool.

geetarman
October 21, 2012, 03:35 PM
These are 20 round magazines. I only load them with 10 rounds.

I am going to take those two apart tomorrow and look at them.

velocette
October 21, 2012, 03:52 PM
Geetarman;
I too have an LR 308. I have 5 magazines, one 10 rd, two DPMS 19 rd and two C products 19.
From new, I disassembled all of them, deburred the feed lips, rounded and chamfered the tabs that stick out ahead of the feed lips, back tapered the front edge of the magazine where the bullets rub across when being fed.
Then I removed the casting flash & nub (sprue) [where the plastic is forced into the die] from the magazine follower, cleaned the inside of the mag & then applied a dry lubricant to the inside, outside, the spring and to the follower.
I have never had my LR 308 fail to feed or suffer any malfunction ever in almost 5 years of shooting it. I suspect that if you do the same to your mags, you too will have trouble free shooting. If that fails, replace the mag.
By the way, the work I did on my 308 mags is the same that I do on EVERY mag I own. Excellent reliability is the result.

geetarman
October 25, 2012, 08:36 AM
^^^^^^^ How in the world did you get them apart?

I talked to DPMS and they said to just return them for replacement.

I can't see how they come apart without using a bunch of force to get the base tab moved over.

It looks like you would have to deform the tab to get it to the point you could remove it.

I can tell that any screw driver that I have will get bent trying to bend the tab up.

What did you use to do that?

velocette
October 25, 2012, 09:21 AM
Geetarman;
I used a small screwdriver to bend down the front of the bottom plate of the mag enough to clear the tab. With the small screwdriver in place, a pin punch in one of the holes of the bottom plate can be tapped lightly with a small hammer to drive the plate forward.
Re-assembly is accomplished by using the same pin punch and small hammer to push the plate back into place.
You can de-burr the feed lips, round the tabs and chamfer the front of the mag without dis-assembly by using a wood dowel to depress the follower enough to allow a stone or fine file to access the lower edges of the feed lips etc.

Roger