What are the causes of a double feed

**CarlosDJackal** · 10-20-08, 12:52

Originally Posted by HES

... Like I said, this only happened with the GA ammo, not the federal.

I missed the mention of GA ammo in the original post. A friend of mine also had issues with their ammo which leads me to think that this is probably the culprit. Have you tried these through a different rifle? Also, you might want to try and run a third brand through the same magazines (make sure that mark them before hand) to see if this happens again. If the third brand does not have an issue, then it is the GA arms ammo.

Good luck!!

P.S. Just because you can't shoot, it doesn't mean that you can't go to the range and watch you wife shoot, does it?

**Heavy Metal** · 10-21-08, 22:03

Usually magazine related.

Sometimes overfunction related.

Sometimes buffer and spring related.

Sometimes tolerance stacking between the upper and lower.

The last three are rare and two and three are essentially the same thing.

Try a heavier buffer for shitz n' grins.

**Hootiewho** · 10-22-08, 18:26

Friend,
Dump the GA arms ammo. I have posted this over and over warning people of the dangers of that stuff. I personally spend a good bit of time one day on a range in a remote area having my Father pick pieces of blown primer out of my face with tweezers from their "168 grain Match .308 ammo". Thank God I was wearing eyepro. The 5.56mm stuff gets even better as it has been the culprit of several Kabooms on AR15's. Do a search, I am sure something will come up. They use SAW (M249) brass for their remanufactured 5.56mm ammo dubbed Canned Heat. The chamber dimensions (headspace) on the SAW are somewhat different than what a 5.56mm AR is even more so than a .223 AR. What happens is the brass gets stretched somewhat during firing in the SAW. IMHO, their ammo is not safe. My incident happened in a bolt action rifle, and I almost never got the bolt free'd up from that incident. In the batch of 500 rounds I bought, I had more than 15 pop'd primers. I suspect that the brass from the .308 ammo was fired in the M240 as it was Lake City brass.

Link to M4 & M249 headspace info:
http://www.ar15barrels.com/data/headspace.pdf

9.95 times out of ten with two loaded rounds double feeding, it will be a mag related problem.

Keep an eye out on the training course announcements in this forum and the next time a man named Dean Caputo gets anywhere near your AO, drop the $250 on his class and go. It will be the best $250 you spend if AR's are your game, trust me. Two days with him will save you a lot of time in diagnosing malfunctions and knowing what it takes to make this weapon system run.

**jh1** · 10-24-08, 17:14

I had the same problem with hte ga ammo& i was using used orlite mags so i was'nt sure what the problem was i'm sure it's the ammo now.

**CLHC** · 12-06-08, 01:35

Excellent thread! This is what I've experienced tonight while at the range. Everything that I was using, I bought NIB. Here's what I have:

Noveske n4lr (now=l-lrlp-556)------->>>http://noveskerifleworks.com/cgi-bin...since=&status=

The add ons/swap (that required some disassembly to said rifle) that was done to it were MagPul's UBR and MIAD.

Ammunition was cheapo Remington 55 gr FMJ. In fact these same ones here still:

http://m4carbine.net/showthread.php?t=17506

Magazines used were MagPul's PMAG. Up till now, only a thousand rounds ran through said Recce. Rifle was and is clean[ed] before the shooting session. First go round, it shot fine. Second go round, first PMAG ran dry and changed out to number two (2) PMAG. "Bang-Bang"--then nothing! Did a quick turn to the side and saw two (2) rounds as is the discussion here. Kinda sorta close to what's illustrated by HES.

Dropped the PMAG, pulled the CH and locked the bolt back whereupon both catridges fell. Inserted PMAG till dry and topped off the session with my Glock 19.

As soon as I get home, I examine my n4lr to see what's up with what I experienced. Recce's clean, well lubed, but did notice something that was not there before. There appears to be a "gouge" of some sort in the chamber(?) with "white metal shavings"(?)(!) I did feel it and sure enough, it is a "gouge/scrape" of some sort on the top portion inside the chamber(?). Hope that it's no cause for panic! Any thoughts on that?I would take a picture, but don't have the digicam anymore.

Going to the range again tomorrow and "see" if it does the "double feed" again. Hopefully, maybe, it's nothing. But better for me to have found this out now than when. . .

**OneKYards** · 12-23-08, 12:14

Originally Posted by HES

Ok I'm mystified as to what can cause a double feed. My wife was having them towards the end of the day today. Here is the scenario

Colt 6920 (the bolt is not colt, but the carrier and everything else is)
Total shots fired: 146 rounds
Magazines: US GI 30 and 20 round types
Shooting positions used: Sitting, prone (both with 20 round magazines) standing (with 30 round magazines)(magazines were never used as a monopod)
Federal XM193...no problems all day
Georgia Arms 55gr FMJ - that's when the double feed problems occurred.

Now I have experienced the same problem when using GA in the past and am inferring that its the GA ammo. My question though is why? What would be wrong with the ammo that would be causing this.

Yes, many definitions on a double feed. A few tips for prevention: Change out your GI followers with MagPul anti-tilt followers. Buy MagPul magazines if you can get your hands on them. Make sure the magazine is being held in tight. Could be the mag or the mag release if it happens on diff. mags (magPul included)

**FromMyColdDeadHand** · 12-23-08, 12:22

Originally Posted by Iraqgunz

Please explain what you mean by double feed. If you mean 2 live rounds attempting to feed at the same time then it is magazine related. More than likely the magazine spring is worn. 20 rd mags aren't know for being the most reliable.

I always thought 20s were more reliable. No kink in the mag body. Now, most 20s will be older, so worn springs and feed lips may be more the norm.

Did anybody have him take a mag and smack the bottom to try to get rounds to eject?

**T-TAC** · 12-27-08, 14:30

I've seen alot of the newer AR's running the heavier extractor spring with the"Black" insert. The older lighter spring used the"Blue" insert.
I've also seen a variance in how hot ammo is loaded lately.
So what I'm thinking is your ar has the heavier spring and combing that with the lighter loaded ammo and there's the problem.
I run the lighter spring and don't find even my shorter ar's having extraction problems. I also find with the heavier spring the empty casing eject at 1-2 oclock from the gun which is discerning in my sight picture. Perferable is 5-6 oclock which makes for a nice neet pile to my right and behind me. But even a 3 oclock pattern is fine.