Glock Mag lower design flaw?

[bmiller]

I have been playing with a pcc that takes glock mags.  Had this happen at a local indoor match over the weekend.  I have looked at various lowers, and haven't seen any that support the mags in the front at point of breakage.  Has anyone else had this happen? I am thinking about putting in some material to support the mag.  I talked to a friend who uses glock factory mags and he said that has never been an issue.  

[Maximis228]

Sounds like a mag issue.

[Aircooled6racer]

Hello: I would try factory Glock mags and see how that works for you. I have seen all plastic 10/22 mags melt down with very heavy use from two kids shooting. One loads and the other shoots and then they switch. Then they call dad over and say they don't work any more. Dad says use the factory mags and off they go shooting again. Problem solved. Thanks, Eric

[Darqusoull13]

This is an ETS mag specific issue. I've had several crushed followers in my JP PCC. I cannot replicate the issue with any factory GLOCK mag. I still like the ETS mags for practice though since I have so many of them. 

[TRUBL]

Soooooo close on the REAL design flaw!!

At any rate......I'll have a fix for that out soon. Even have a patent pending on it  

Tim

[IntenseImage]

Soooooo close on the REAL design flaw!!

At any rate......I'll have a fix for that out soon. Even have a patent pending on it  

Tim

Ejector is the same as the mag stop?

[mksm2016]

What brand is the lower receiver? NFA or others?

[bmiller]

PSA billet glock.  I really like it.  I can monopod on the mag and the gun still works.  I have looked at the PSA lower with the bolt hold open, which I THINK is a NFA. The JP lower is the same as the PSA relative to this problem.

[Bamboo]

Is that from the gasses blowing back during ejection and overheating the plastic?    Did the gun still run or did that stop it?

 

[Flatland Shooter]

6 hours ago, Darqusoull13 said:

This is an ETS mag specific issue. I've had several crushed followers in my JP PCC. I cannot replicate the issue with any factory GLOCK mag. I still like the ETS mags for practice though since I have so many of them. 

Is the ETS mag made of hard or brittle plastic?   My Glock mags are made of a polymer material that flexes a little bit.  That may keep them from breaking.

I also stuck a magazine in a Glock 17 to see how it lines up.  Where the PSA lower leaves about a 1/4" gap between the front of the magazine and the barrel, the G17 runs almost flush.

So this may be only a problem for the Glock based AR's.

Brian's idea to add some material (aluminum?) to support the front of the magazine has merit.  Fill up that empty space and it would not only keep the magazine from flexing but also direct gases above the magazine.

[bmiller]

1 hour ago, Bamboo said:

Is that from the gasses blowing back during ejection and overheating the plastic?    Did the gun still run or did that stop it?

 

The gun was running, but poorly with that mag. Had some nose dive jams.  At ULASC, I had to pull the mag from the rifle.  As for the gasses heating the mags, I didn't think of that. Now I am going to have to do a mag dump and check the temp of the mag.

[bmiller]

26 minutes ago, Flatland Shooter said:

Is the ETS mag made of hard or brittle plastic?   My Glock mags are made of a polymer material that flexes a little bit.  That may keep them from breaking.

I also stuck a magazine in a Glock 17 to see how it lines up.  Where the PSA lower leaves about a 1/4" gap between the front of the magazine and the barrel, the G17 runs almost flush.

So this may be only a problem for the Glock based AR's.

Brian's idea to add some material (aluminum?) to support the front of the magazine has merit.  Fill up that empty space and it would not only keep the magazine from flexing but also direct gases above the magazine.

Up until the past weekend I have had zero issues with the ETS mags.  To their credit I called them and told them about the issue  and they are replacing the broken mag plus the one that is dented and not broke yet, no their dime no less!  I would say the plastic they are made of is harder than the factory glock plastic.  There isn't any metal reinforcement in them.  In turn the Ets mags could be more brittle. I have no way of testing any of this, I am just going off of feel.  I have some old police trade in g-22 factory mags that are beat up in the same area.  I wonder if there were police departments running .40 cal pcc?  

[RigPig]

Good to hear ETS is going to stand behind their mag, even though it was a casualty of what looks like a design flaw of the lower. I run exclusively ETS mags in my competition Glocks and have a dozen of the 31s for my PCC.

[atomicferret]

I have heard (on different occasions, from different manufacturers) that the clear polymers are generally less durable than opaque ones.  I have heard it is one of the reasons Magpul doesn't make a clear magazine or furniture.  Which is too bad, because I would love to have a clear stock and handgaurd to finish out my "ghost gun". 

 

I think the ETS are cool, but I would only use them for practice. 

[Aircooled6racer]

Hello: I wonder if the powder residue is breaking down the plastic as well just like the tinting of the Dillon powder measure does with Tite Group and some other powders? Thanks, Eric

[bmiller]

Possible, but this mag was clean and and really didn't have that many rounds on it when it broke.

[wgj3]

Eric makes an interesting point. Would be weird, but certainly possible that some powders/powder residue have the effect of weakening the ETS mag material. I have been running mine with Bullseye primarily and haven't had a failure of the same nature at this point.

[corny]

Looks like the bolt is striking your mag.  See if someone has another Glock PCC bolt and mic it.  May be it is striking the mag until it fails.

[bmiller]

I really don't have a way of verifying this, but the new mags they sent me seem to be a little tougher:  When you squeeze them, they feel a little different like they changed polymers or something.  The spring is much stiffer.  My theory is maybe the the gen one spring was allowing the round to partially nose dive and slam into the front portion of the mag, then it popped up into the chamber.  The lower does not support the front of the mag, so eventually the polymer mag gave way. I checked for the bolt dragging early on, not an issue. I used factory glock mags yesterday, the gun ran like a sewing machine.  I am finally confident in this rifle. It came with the chamber cut too deep, and it had a soft extractor from the factory.  A friend bought a PSA rifle the same time as me and he has had zero issues.  I think he just cleaned it for the first time after putting 1500 to 2000 rounds through it.  Luck of the draw I guess!

Edited February 6, 2017 by bmiller

[JonF]

I think there is a combination of factors/forces there. To characterize the movement, when cartridges are feeding from the mag, the bolt pushes them forward and as they slide from the mag feed lips, the nose of the bullet will strike the front wall of the magazine body where yours cracked. Since the cartridge is angled slightly upwards, it should begin to tilt and slide upward along the mag body front wall then transition over the mag body and into the chamber.

 

Now to facilitate reliable operation (and knowing that the mag body will take this sort of repeated beating), glock themselves made sure to extend the inner metal shell up into the tab that acts as a feed ramp or guide in the mag body. Without it, the flimsy nylon would just bend or snap like yours did above. Supporting could theoretically help, but not even glock pistols are supported in that position. My old DDLES receiver is not supported there either.

 

It also seems that there is more reciprocating mass, speed or force in the movement of PCC actions therefore the mag feed ramp takes a greater beating. While i only use oem glock mags now, i have in the past also tried KCI mags and can say that on occasion when i get a round that did not feed cleanly (or feeding blunt JHP or TC bullets), the round will sometimes nose dive during feeding and hammer so hard into the glock mag feed ramp that it bends it forward just a little. IT doesn't create a problem for feeding, however, it makes the mag NOT drop free so you have to yank it out and then hammer the ramp tab back into place. Doesn't happen very often when i use round nose so i dont get it much anymore but it does happen on rare occasion.

 

So what ammo are you using here when it happened?

[bmiller]

I was using 105 grain truncated cone bullets that were relatively short.  I switched to 95 grain round nose bullets, it ran like a scalded dog last weekend.

[JonF]

The flat nose is, without a doubt, more difficult in feeding and beats up the feed ramps. Short OAL's create even more of a hammering effect. When i switched from JHPs to RN fmj, i got rid of all my feeding, jamming and bending issues also.

[bmiller]

I recently tried a some precision delta 95 fmj bullets. They fed perfectly, and were more accurate than any other light bullets I tried.  Haven't seen any marks on the front of the Ets mags like before.