Another SA Friday Ed Thread; Glock Mags

[SA Friday]

This has come up twice in the last three days, so I thought I would post a thread about some of the info I've come across over the years about Glock Mags.

First and foremost, all Glock mags of the same caliber have the same dimensions from the bottom of the mag retention notch to the feed lips. What does this mean? It means a G22/35 mag will fit into and function in a G23 or G27. A G23 mag will fit into and function in a G27, but won't work in a G22 or G35 as it's too short to work. This works for all the various Glock models. As long as the caliber is the same, the longer mags function in the smaller guns. Why would anyone want more than one or two G26 or G27 mags? I don't know. I carry a G23 or G22 mag to reload to with my G27 when I carry.

Second, The above concept doesn't work if you convert a G20 to 40 S&W. No Forrest, the G22 mag won't work in the G20 once converted. [Tooth]

You CAN get G17 and G22 and G20 and G21 mags to carry more rounds. There are three companies that make extensions for these mags that I trust; Taylor Freelance, Arredondo, and Dawson Precision. You know those one and two round extenders you see all the time? Complete junk. Don't bother with them. I've seen those things cause more Glocks to puke or explode on the impact with the ground during a reload... They just are not quality products. The three above work. If you do extend a mag with these extensions, you have to change the mag spring to a Wolfe +10% spring. If you don't the spring will be too short and too weak to operate reliably. The pay off is +5-6 rounds of 9mm and +4-5 rounds of 40 S&W.

If you have to take your glock mags apart to clean regularly, you know those little tabs on the top of the side rails on the body of the mag for the floor plate make disassembly a real pain in the ass. All the mags I use for competition, I take the floor plate off and then use and Exacto blade and CUT THEM OFF. In 7 years of doing this, I have never lost a floor plate or had one even come loose with the tabs removed. They are a needless example of over-engineering. I've wore out glock mags in one years of shooting. That's how many times they get dropped, stepped on, kicked, dirt, mud... Never lost a plate.

Glock mags will wear out. When the sides bulge to the point the mag will not drop free, either throw it away or set it aside for practice only. You cannot bend it back into working shape. Trust me on this, I've tried. The mag is shot. Don't use it for anything you want it to fall free during.

Any Glock mag that has a U shaped cut in the back on top is junk. Throw it away, NOW. These are the old "won't drop free, and will screw you in the butt when you need it to drop free every time" mags. Rid the earth of these mags.

Any mag made for Glocks NOT made by Glock is junk. Once again, rid the earth of these.

Glock mag feedlips WILL spread in the front after lots of use, especially the 40 cal mags and the 45 cal mags. If you have used mags that constantly jam, the feel lips are probably spread out. Rid the earth, replace. Bend all you want, they will spread in two or less uses...

Glock mag springs WILL die. You leave the mag loaded in the safe, you kill the springs after about 6 months. There are no magical mag springs out there that never die. This is a myth. I've heard this myth perpetuated for years now. No magical springs, replace the mag springs regularly and you will be fine.

Glock numbers their followers. The bigger their number the newer version they are. I have yet to find any design that works better or worse than the other as long as it came from a mag with the square notch on top instead of the U notch.

Don't use lubricants or oil on a Glock mag, EVER!!! Run it dry.

Basically, if in doubt, throw the mag away and buy a new one. Glock mags are cheap and there is no reason to run a bad mag. Besides if you are not shooting enough to wear out a mag or two during the year, you probably are not shooting enough. [Tooth]

[iamhunter]

good info, thanks

[Ridge]

True, true...I conceal carry this:

http://i17.photobucket.com/albums/b100/89Sunbird/Shooting/DSC_0005.jpg

[275RLTW]

Well said.

[Driftwood]

Any mag made for Glocks NOT made by Glock is junk. Once again, rid the earth of these.

That's for darn sure! +1. Folks, don't be tempted by these 8-9 dollar Korean mags. They're fine for range practice, but DON'T USE THEM FOR CARRY MAGS!


Glock mag springs WILL die. You leave the mag loaded in the safe, you kill the springs after about 6 months. There are no magical mag springs out there that never die. This is a myth. I've heard this myth perpetuated for years now. No magical springs, replace the mag springs regularly and you will be fine.

OK, this is the first I've heard of this. I don't think it's accurate. From everything I've researched, it's not leaving rounds loaded in any magazine that causes damage, it's the constant reloading and unloading that weakens springs in any magazine.

[BigBear]

Rgr that SA. Good writeup. I have the two that came with the wife's G26, and then she has 2 hi-caps for my G19 that work great in the G26 as backup.

[MrPrena]

That's for darn sure! +1. Folks, don't be tempted by these 8-9 dollar Korean mags. They're fine for range practice, but DON'T USE THEM FOR CARRY MAGS!



OK, this is the first I've heard of this. I don't think it's accurate. From everything I've researched, it's not leaving rounds loaded in any magazine that causes damage, it's the constant reloading and unloading that weakens springs in any magazine.

+1

ETA: BEst way to find out the myth is to have 2 mags loaded.
Have 1 mag kept loaded for 6 month. Another one to be loaded and unloaded every week.
Then, take the mag spring out after 6month from those 2 mags and apply same mass on top.
Whichever compresses more is the loser. :D


There is better way to calculate this, but more math involved. Don't feel like doing math at 92F today....

[SA Friday]

That's for darn sure! +1. Folks, don't be tempted by these 8-9 dollar Korean mags. They're fine for range practice, but DON'T USE THEM FOR CARRY MAGS!



OK, this is the first I've heard of this. I don't think it's accurate. From everything I've researched, it's not leaving rounds loaded in any magazine that causes damage, it's the constant reloading and unloading that weakens springs in any magazine.
Nope. By leaving them loaded for long periods you are setting memory into the coils, memory of full compression. I have fixed dozens of Glocks at various ranges over the years by simply disassembling the mag, stretching out the spring and reassembling. Every time, the mag was left loaded in the nightstand for at least half a year. Stretching them only works for a little while, and then they start crapping the bed again. This is consistant with any gun mag, not just Glocks. Loading and unloading the mags has it's amount of wear and tear on the mags too, but not even close to leaving the mag fully loaded for months on end. If what you are saying is true, wouldn't Glock store, ship, and recommend leaving the mags fully compressed? They don't.

[Elhuero]

Any other wives tales to share?

[SA Friday]

True, true...I conceal carry this:

http://i17.photobucket.com/albums/b100/89Sunbird/Shooting/DSC_0005.jpg
OH YA! This picture reminded me of another tidbit of info. Those stickers on the side of the mags that the factory puts on there or the wholesaler puts on there... I've seen them roll in to a nice ball upon insertion into the gun's magwell and jam that mag nice and tight up in there. Take them off and if there's residual stickyness, clean it off with rubbing alcohol or Goo-Gone. Goo-Gone is made from citric acid and works better than anything I've found for this. Smells like oranges too, mmmmm.

[Irving]

The point is that springs wear out from use, not from being either fully compressed or fully at rest. Any stationary point should be fine.

I'm sure I could Google it, but you don't happen to have a picture comparison of the Square backed and U backed mags do you? I have a feeling you've thrown out all the U backed ones you've ever had though.

[SA Friday]

Any other wives tales to share?
Ya, don't hold your breath till you pass out. You look like a Democrat when you do this. [Tooth]

[Elhuero]

Ya, don't hold your breath till you pass out. You look like a Democrat when you do this. [Tooth]


hehe nice [ROFL1]

[Driftwood]

American Handgunner: Magazine spring madness: 'creep' to your 'elastic limit' to un-earth the urban legend of 'spring-set' (http://www.findarticles.com/p/articles/mi_m0BTT/is_163_27/ai_99130369)

The shooting sports are full of some of the most knowledgeable and capable people you'll meet anywhere. I've been impressed consistently with the abilities of those I meet at the range to diagnose and fix a gun problem with as little as some spray lube and a cotton swab. However, sometimes a myth will creep into the folklore.

The magazine spring myth has been around for many years and is growing in popularity. It goes something like this: "You should unload your magazines when they're not in use or the spring will weaken causing failures to feed." This has gone as far as shooting competitors actually unloading their magazines between stages to extend the life of their springs. A variant of this myth is: "You should never load a magazine to capacity and should always leave it one round short." What if you need that round some day?

Recently, I read an article in a gun magazine suggesting you rotate your magazines so the ones not in use can "recover and rest." The same author uses the phrase "spring-set" to describe weakness of a spring because it was compressed for a long time. Hogwash. There's nothing further from the truth. Springs don't care how long they're compressed and don't require rest, recreation or even a vacation from time to time.

Shameful Spring Benders

To put this one to rest, you have to understand creep. Creep is the slow flow of a non-ferric metal like copper, brass and lead under force. At temperatures outside of a furnace, steel doesn't have any appreciable creep. Under most conditions, steel flexes and then returns to its original shape. When pushed past its elastic limit, steel will bend and not return to its original shape. All designers of well-made magazines make sure the spring never approaches the elastic limit when the magazine is fully loaded. Honest. This means the spring will not weaken when the magazine is fully loaded -- not even over an extended time. Like 50 years. American Handgunner recently ran a story about a magazine full of .45 ACP that had been sitting since WWII and it ran just fine on the first try. So there you go.

Now that the light of truth is leaking out, lets talk about what is causing failures to feed. The only way to weaken a magazine spring is to flex it past its normal range (elastic limit). If this is happening, somebody is trying to overload a magazine or has "adjusted" it by bending the spring. Both of these could cause feed failures. Shame on you if you're a spring bender.

Carlton Nether, Customer Service for Beretta USA, tells us keeping a pistol magazine loaded for an extended period doesn't cause magazine spring failure, however, failures to feed can result. He says, "The ammo will 'roll' in the magazine. If the mags are kept loaded and moved around a lot -- say on a cop's belt -- the rolling action can, over time, cause creases in the cases. These creases can cause malfunctions. Also the top bullet will roll against the magazine lips and creasing can occur there as well. Just check old ammo that's been bouncing around in a magazine for a long time.

We tell police officers if they keep loaded magazines, take a few seconds to "cycle" the ammo. Periodically unload the mag and reload it in a different sequence. This movement will allow the bullets to be in different parts of the magazine and help eliminate creasing.

At STI, Dave Skinner, President and CEO says, "Personally, I rotate my 'under the bed' and 'under the seat' mags about every six months. I always empty them the 'fun' way and have never had a failure." Given what we learned above, this sounds like a good idea. Smith and Wesson customer service also says magazines can stay loaded indefinitely without hurting the spring.

As we add force onto a spring, it will displace the same amount for each amount of force we add. This is true until the spring passes a certain point called the elastic limit. Robert Hooke discovered this theory back in 1660. Hooke's Law states: "If the applied forces on a body are not too large, the deformations resulting are directly proportional to the forces producing them." Which means, in actual human being language, if we load a spring past its elastic limit, it permanently deforms. It still provides a force against the load but the force is no longer proportional. If this happens, when we unload the spring (such as when we empty a magazine that has been over-loaded) the spring never returns to a state where it can provide the same load for the same amount of displacement.

Trust Us

When a magazine manufacturer designs a spring, they plan for a preload. The spring is already compressed some in the magazine. On the curve below, this would be Point A. The spring compression would be designed to be below the Elastic Limit. When fully compressed, the spring would be at Point B. If the spring is ever compressed past the elastic limit, say to Point C, it won't ever behave the same. Like a recalcitrant lazy Uncle, it will have a lower spring force for each amount of displacement. On the drawing, the spring would now cycle between points D and E. This means that -- particularly with the last bullet or two -- the force pushing the bullet up would be less and lo-and-behold, a mis-feed might occur.

When somebody stretches your spring to "fix" your magazine, they are trying to get you back on the original curve. They may get pretty close, however, it's unlikely the spring will ever perform to its original design. The elastic limit is now shifted lower and your magazine spring may fail to perform fairly quickly.

Having said all this, if you have a magazine that isn't feeding right, what should you do? First, disassemble the magazine and clean it thoroughly. Then try it with new, factory ammunition in a freshly cleaned gun. This takes away some of the possible causes. If you are still having feed problems, send it back. Even the low cost, after-market magazine manufacturers will fix the problem at no cost to you other than shipping. If it's a magazine from the gun's manufacturer, let them troubleshoot and repair the problem. Otherwise, toss the mag. It's not worth risking your life to save a few bucks. And that's the truth.

RELATED ARTICLE: Definitions

Creep: The flow or plastic deformation of metals held for long periods of time at stresses lower than the normal yield strength.

Elastic Limit: The maximum stress that material will stand before permanent deformation occurs.

Yield Strength: The stress at which the metal changes from elastic to plastic in behavior, i.e., takes a permanent set.

Permanent Set: Non-elastic or plastic, deformation of metal under stress, after passing the elastic limit.

Magazine Recommendations

* Clean your magazines when they get gritty. Apply oil then remove all excess. Oil attracts dirt that may cause malfunction.

* If you find rust on the spring, this is culprit. Rust changes the thickness of the metal and reduces the force applied to the follower. Cleaning off the rust may help. For a gun you depend on, replace the spring. All the major brands and most of the smaller ones have replacement mag springs available or try Wolff Springs.

* If you keep a magazine loaded for long periods, rotate the rounds every few months. If you carry a pistol on the job or in your car, cycle the ammo frequently. These actions prevent creases from forming which may cause a misfeed.

* If you experience feed problems, first clean your magazines and weapon. Fire a couple magazines of new factory ammo to see if this resolves the problem. If not send the magazine back to the manufacturer -- or toss it.

[Jer]

Some good information but some inaccurate information as well. The most glaring of which being that a factory Glock mag goes Tango Uniform if fully loaded for six months. This simply isn't correct.

[SA Friday]

Some good information but some inaccurate information as well. The most glaring of which being that a factory Glock mag goes Tango Uniform if fully loaded for six months. This simply isn't correct.
Test it. I did. I have three dead Glock 23 mags in the basement.

[ChunkyMonkey]

I have both the korean and glock mags loaded for over a year... shot few mags couple weeks ago. They worked fine - however, I ll unload and check out the other 4 unshot and compare the springs to new ones.

[Hoosier]

Test it. I did. I have three dead Glock 23 mags in the basement.

I had a loaded mag in a G23 in a book that I forgot about, 3 years later it ran fine. Perhaps it's a YMMV issue. I have a stupid large number of .40 cal glock mags, and have never had an issue.

In fact, that G23 was the first gun I ever bought, it's a 1997 vintage, and has never misfired on me. There were times early in it's life when I didn't even clean it after every trip to the range. Love me the glocks.

H.

[SA Friday]

I'm sure I could Google it, but you don't happen to have a picture comparison of the Square backed and U backed mags do you? I have a feeling you've thrown out all the U backed ones you've ever had though.
Here's a pic of the mag bodies by generation; left is earliest to right the most current.

[Irving]

Thanks for the picture, I can easily see the "U" shape.