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View Full Version : How far is too far for magazine feed lips to spread?


aaronb
05-24-10, 20:29
I asked this a different way but haven't got an answer yet. I think I didin't ask the question well enough and was to vague.

Does anyone know how far the magazine feed lips can spread before the magazine is no good? The reason I ask is that a rifle at work had a cartridge jamb between the charging handle and bolt. The rifle was stored in a car rack with the bolt locked open. I think the round was just jarred loose from driving but wanted to eliminate the magazine as the issue.

Thanks,

Aaron
mark5pt56
05-24-10, 20:38
If it popped out from road bumps--chuck it--it's done.

A general test is to "pop" the bottom of the mag with your hand and if a round(s) pop out the feed lips are spread and the mag spring is weak.

I can usually "eyeball" the mag and tell.

You can also measure a few new ones and have an idea of what they should be.
Quib
05-24-10, 20:44
The Army actually has a gauge out now for checking the spread. But I’ll be damned if I can find info on the specs of the gauge!
they
05-24-10, 22:41
Two things should make you stomp on a mag...

... mag causes a malfunction.

or

... mag feedlips are "noticably" spread... if you can notice it... you need to throw it away.
mark5pt56
05-25-10, 05:34
You can also get a pmag cover and it has an built in "gauge" I'm sure someone has one laying around from one. Not sure, but it should be close as a G.I.

Once you measure a a couple new GI's for a cross reference, make one if you need it.
Quib
05-25-10, 06:34
You can also get a pmag cover and it has an built in "gauge" I'm sure someone has one laying around from one. Not sure, but it should be close as a G.I.

Once you measure a a couple new GI's for a cross reference, make one if you need it.

The PMAG cover came to mind, but are the specs the same for both PMAG and GI aluminum mag openings?
Treehopr
05-25-10, 08:23
I believe Kyle Lamb teaches to load a 30 rd magazine with 15 rds and then slap the bottom of the magazine.

If a round pops out then the magazine is bad, doesn't exactly answer the feed lip dimension question but may help with troubleshooting bad magazines.
Sparky5019
05-25-10, 08:29
You can never spread any lips too wide!!:D


Oooh, you were talking about MAGAZINES...uh, what Quib and the others said!

Sparky;)
ForTehNguyen
05-25-10, 10:19
The PMAG cover came to mind, but are the specs the same for both PMAG and GI aluminum mag openings?

for the lips I dont see why they would be different, they all have to fit in the same magwell.
NongShim
05-25-10, 13:31
I believe Kyle Lamb teaches to load a 30 rd magazine with 15 rds and then slap the bottom of the magazine.

If a round pops out then the magazine is bad, doesn't exactly answer the feed lip dimension question but may help with troubleshooting bad magazines.

Yeah, this is pretty much the easiest way to tell if they're worn out. I've never used or even seen an actual guage. The method Lamb teaches is just fine.
Quib
05-25-10, 18:25
To ensure the magazines that are in the system are up to standard, PM Soldier Weapons will be making a magazine wear tool available this fall that eliminates guess work when it comes to identifying unserviceable magazines. The tool will enable armorers and supply supply sergeants to precisely gauge whether the separation between the magazine feed lips are within specifications – a critical parameter for magazine performance.


http://farm5.static.flickr.com/4005/4177506544_6050b95214_b.jpg
Quib
05-25-10, 18:46
for the lips I dont see why they would be different, they all have to fit in the same magwell.


Outer mag dimensions effecting the magwell fit, are different than those of the feed lips.

Doing a quick measurement of a new GI mag verses a PMAG of the latest revision, the GI mag measures in at approx. .474", while the PMAG measures in at approx. .450". A difference of .024"

At first glance, there seems to be a difference. One would tend to think the dimensions would be the same. I guess that would be a good question for a rep of Magpul.
mark5pt56
05-25-10, 18:53
Yeah, this is pretty much the easiest way to tell if they're worn out. I've never used or even seen an actual guage. The method Lamb teaches is just fine.


A general test is to "pop" the bottom of the mag with your hand and if a round(s) pop out the feed lips are spread and the mag spring is weak.


hmmmm-----
mark5pt56
05-25-10, 19:04
Outer mag dimensions effecting the magwell fit, are different than those of the feed lips.

Doing a quick measurement of a new GI mag verses a PMAG of the latest revision, the GI mag measures in at approx. .474", while the PMAG measures in at approx. .450". A difference of .024"

At first glance, there seems to be a difference. One would tend to think the dimensions would be the same. I guess that would be a good question for a rep of Magpul.

Tango Down--.425
newpmags-.445-.450
old pmags--.460-.470
GI-old ones, no new ones out--.460-.480, had one at .490--could tell it's wider

This my batch
Quib
05-25-10, 21:06
Tango Down--.425
newpmags-.445-.450
old pmags--.460-.470
GI-old ones, no new ones out--.460-.480, had one at .490--could tell it's wider

This my batch

Good info Mark......lots of variance there!
Quib
05-28-10, 20:09
Specs of the new feed lip tool.......

http://https://www.fbo.gov/download/dd3/dd32280a666d9cfbd8aef889d176f756/13023560-M191B147_-_TopDWG_-_Distribution_Code_A.PDF (https://www.fbo.gov/download/dd3/dd32280a666d9cfbd8aef889d176f756/13023560-M191B147_-_TopDWG_-_Distribution_Code_A.PDF)