No, It Doesn’t Take Glock Mags…and Sometimes That’s Better

Sometimes it makes sense to use convenient existing magazines. Sometimes it doesn’t. Like all things in firearms design, magazine features are all compromises. Single feed vs double feed, polymer vs steel, and straight vs curved…one size does not fit all.


  1. One not mentioned benefit of double feed mags is that you can cram additional round or two in the same overall length compared to single feed; that can be great for one trying to make a highest capacity standard magazine pistol.

  2. Yes it would be good if there some standardization! I guess the bean counters would not like that! In my case The wide variety keeps my from certain pieces.

  3. Should have mentioned that double feed magazines are easier and faster to refill, and don’t require magazine buttons or reloading tools. Just push the rounds straight down between the feed lips.

    I won’t even go into the aesthetics of a slanted glock magazine in a PPC (pistol caliber carbine).

  4. Another potential drawback of Glock mags is that 9mm Glock frames are shared with .40s. Since .40s fully double-stack, this means the grips are really .40 grips; combined with the polymer thickness Ian covered, this means they are significantly bulkier than purpose-built steel 9mm mags (P365, etc.). This is further reinforced by the fact that aftermarket metal mags for “single-stack” Glocks fully double-stack 9mm.

    On the other hand, while there are theoretical reliability advantages for double-feed, the extended Glock mags have a phenomenal record. Out of 483 Midway reviews, 1 is one-star, 1 two-star, and zero three-star reviews; both low reviews are unanimously thumbs-down (regarded by other reviewers as operator error, etc.). I know some positive reviewers are just being loyal or “nice”, but not all 481.

    • Not really. The .40 Smith & Wesson was brought to market in 1990. The original Glock 17 is from 1982. Designed for the Austrian Army trials. But the plastic magazines are thick to ensure durability and function and the grip size follows.

      • What you wrote seems like a valid point, and I did consider it. I certainly have no argument on the timeline, although Glock is on its fifth generation of pistols and several generations into mags as well. Without a first-gen mag or frame for comparison, I have no way of tracing how or why it evolved that way.

        The fact nevertheless remains that .40 Glocks fully double-stack, as opposed to the “stack and a half” that results when one retrofits .40 into a lean purpose-built 9mm envelope. 9mm Glock mags (being plastic) don’t have the telltale ribs, but they’re thicker than ribbed P320 mags, and almost as fat as double-stack 1911A2 mags meant for .45!

  5. Having lived through a mag ban, my 3-D printer is whirring away right now printing another Glock mag. Is the Glock mag the best pistol mag? Objectively, it is not – but the market has spoken, and quantity has a quality all its own. When the Supremes recognize that capacity limitations are infringements on the 2nd, go nuts w/ different mags; with the possibility we could lose the Senate, print and buy as many Glock mags as you can.

  6. How much does cartridge shape affect magazine reliability? 5.56mm/.223 Remington has a pronounced taper (so do 9mm and 7.63 Luger). The standard 20 round M16 magazines have a sloped floor, which to my ignorant eye would affect the angle and pressure from the magazine follower.

    • Cartridge profile can be critical. One reason 9 x 19mms tend to be reliable in feeding is that the cartridge case is tapered; combined with the usual round-nosed bullet profile, it tends to guide the round into the chamber, regardless of magazine feed geometry.

      The 5.56 x 45mm/ .223 is essentially a scaled-down 7.62 x 51mm/.308. So its feed geometry is more that of an only slightly tapered straight-wall case. Compare it to the original .222 Remington or the .222 Remington Magnum; both have significantly more body taper aft of the shoulder than the .223 does.

      One problem U.S. Army Ordnance had in the design R & D chain that led to the M14 rifle was that the basic M1 Garand action was designed to feed long cartridge cases with a pronounced taper, first the .276 Pedersen and then the .30-06. The 7.62 x 51 was based on the much shorter, less-tapered .300 Savage. It took considerable work to make the Garand type action work with it, and in my experience M14s are never as feed-reliable as M1s; Beretta BM59s are better but still not up to the .30-06 in that department.

      Probably the most feed-reliable 7.62 x 51 was the original AR-10. Most likely because unlike almost every other 7.62 NATO rifle in existence, it was designed around that cartridge from the start. (The FAL and CETME aka H&K G3 series were originally designed around the 7.9 x 33 Kurz round).

      Generally, the most challenging design procedure is making a Kalashnikov action work with either 5.56 or 7.62 NATO. Because the cartridges it was designed around (7.62 x 39 and 5.45 x 39) both have much sharper case taper than the “American” rounds. This also may explain why the SVD rifle in 7.62 x 53Rmm has a reputation for reliable feeding, even with the .30-30 WCF-shaped rimmed Mosin-Nagant round. The Dragunov Tiger in .308, not so much.

      In pistols, 1911-type actions seem to work best with straight-walled, rimless or semi-rimmed cartridges. This may explain why 1911s in .40 S&W and 10mm Auto tend to feed more reliably than other designs; the cartridges have profiles very like the .45 ACP or .38 ACP/Super. in my experience, 1911s are not happy with 9 x 19mm and tend to have seizures (in all respects) with 7.62 x 25mm.

      The most reliably-feeding 7.62 x 25mm pistol, bar none, is the old Czech Vz52. But it has a single-stack magazine and was designed around that exact cartridge from the beginning.

      The moral is that best way to avoid problems in feeding is to decide which cartridge you are going to use first, and design your weapon around it.

      The magazine is an important part of that design process, but it will only feed as well as the action allows it to.



  7. This might be the stupidest possible time to argue that gun makers have too low a margin. I think a gun maker does itself a great favor by allowing a new firearm to add itself to a deployment/carry rig with an existing set of solid, working magazines. For those of us that do thankless dirty hard labor jobs for each and every addition to our arsenals, expensive proprietary magazines are all but a deal-breaker (FN and AICS are some of the worst for this) On the other hand, great magazines can make a cheap polymer lower do great things. Finally, some magazines are just intrinsically excellent. My 100rd surefire’s are the best metal stanag mags I have ever used. X25 drums are similar. My FNX and CZ75SP01 magazines are of great quality, so much that they cover the floppyness of overheated polymer lowers as an endoskeleton. My real issue is being able to get reliable 25+ rd magazines for pistols, and a PCC magwell to take them. In that respect, Glock is one of the only choices you have. But the only area I feel Glock has a true advantage are 10+ rd 10mm magazines. 10mm PCC’s are cool, and a carbine sized (20-50rd) magazine in 10mm is going to be a Glock mag.

  8. Great talk Ian, I thought you were going to bring up the Hudson 9 initially trying to use a Glock mag until it was a limiting factor on them bringing the bore axis down.

  9. It’s not mainly about expense for me. There’s an obvious advantage in being able to share magazines between my sidearms. I have no idea why you didn’t mention that, except that it tends to undermine your thesis.

  10. The firearms industry is remarkably forward thinking is some areas. And incredibly conservative and behind the times in others.

    Case in point: Magazines. Yes, of course there should be different magazines for different purposes, and there are no perfect magazine solutions, but it IS weird that there hasn’t been more standardization.

    (As with Picatinny rails that finally have gotten to be close to a universal standard.)

    A sizable chunk of the handgun market are virtually identical 9mm guns with a polymer frame, so WHY hasn’t the industry chosen a common magazine standard?

      • “You cannot look at it like its cell phone charger connection…”(C)

        That is how it should be looked at.
        Some manufacturers are too dumb to understand that making a good mag is no less a piece of work than a trigger assembly.

        A simple example from life.
        When a new product was developed at a famous factory, they also wanted to develop their own mag. The rationale was simple, such as “we will trade our own original mags and set the price we want.”
        With some difficulty, they managed to persuade them not to commit this stupidity, but simply copy the most common mag of this purpose.
        The result.
        The carbine works great with mags from most manufacturers, but constantly stutters with “native” mans, although they are an “exact copy” of the prototype.

        • Once already started, the second example.
          The carbine was built under the common mage, manufactured by several different manufacturers.
          The prototype worked flawlessly with all the mags, except for its new own.
          Because, when copying and making the shape for the mag, mistakes were made. And these boobs did not come up with anything better than “fixing” the size of the receiver to “theirs” mag…
          The result.
          The device normally works only with its mags, while the rest are normally installed in it and only sometimes work.

    • You are looking at it the wrong way around. Instead of assuming there should be standardization and you want to know who is gumming up the works, assume there is no standardization and look for the reasons.

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