The problem with any pistol drum snail mag is that you expect it to run over a pound of ammo-- mostly outside of the magazine well-- up a long column and into the chamber under varying spring pressure while the whole affair is held in place by a mag release designed to hold significantly less weight centered in the pistol's grip rather than dangling like a pendulum below it. In other words, the pistol wasn't designed for it, and the mag must overcome this ramp of impending doom.
Nonetheless, the market has been swamped with folks trying to deliver pistol drums and people seeking them out, usually to disappointment for all involved. As Glocks have been one of the most widely circulating handguns of the past 30 years or so, this saw successive waves of cheap imported 50-round drums from the likes of SGM, KCI, Pro-Mag, and others, all with somewhat less than desired levels of reliability.
Magpul has coughed up some "Glock pattern" drums in the past including the D-50 GL9 PCC, which had a short feed tower designed to fit in pistol caliber carbines but would not work in a pistol. Released at SHOT Show 2020 alongside an EV9 variant, the PCC Glock drum was a quick hit and has since proved dependable and popular.
Magpul teased the pistol version at the same SHOT Show event but, due to assorted reasons it only made it through production and hit the market in March 2022.
This brings us to the...
D-50 GL9 Glock Pistol Drum
Debuted earlier this year, Magpul didn't seek to reinvent the wheel and borrowed the same magazine drum body of the successful D-50 GL9 PCC and simply added a tower that mimicked a Glock double stack pistol mag. This made the new D-50 GL9 pistol drum significantly longer than its older PCC mag brother but allowed it to run and play with all those Glock-pattern 9mm handguns out there.
The recommended use of the D-50 GL9 is for a Glock 18 (we wish) or G17/19X/34/45, as you are going to have the most support in the tower but it will also fit smaller-framed double-stack Glock 9mms such as a G19 or G26-- but keep in mind the little guys will give you more "seesaw" over the course of firing, upping your chance for a jam or breaking something. Wiggle is not your friend in a mag. Magpul also says it will seat in the Kel-Tec Sub-2000 carbine while the older D-50 GL9 PCC will not.
On the range
Magpul recommends that users install a new OEM magazine release on Gen 1-3 Glock handguns to support the extra weight of the magazine (keep in mind it is over 2-pounds when fully loaded) and that Gen 4 Glocks will probably need an aftermarket metal magazine release. They also caution that a new recoil spring assembly may be needed to ensure reliable feeding while also saying "individual variations between firearms may result in an extra power recoil spring being required."
With that being said, we evaluated the D-50 GL9 pistol drum in both a well-used "Gen 4.5" Glock G19X and a high-mileage Gen 3 Glock 19, each with no modifications, and had good success.
The mag is designed to be left loaded for storage with no degradation of function and we assessed that by leaving it loaded with a box of 115-grain Federal Syntech for two months. This is what happened when we took that load to the range:
Magpul warns that these drums probably won't work with PCCs, explaining:
Use of this D-50 GL9 in pistol caliber carbines (PCC) is not recommended, because the increased length of the feed tower will be partially unsupported in most pistol caliber magazine wells. This unsupported condition may cause premature wear on the feed tower magazine catch, and (in firearms which deviate from factory magazine well specifications) may result in improper round presentation and failures to feed.
To test the advertised likely failure of the drum to work with a PCC, we ran it in a WASR-M, which runs great with OEM Glock double stacks. Trying it 10 times, it was a single shot each time, jamming on the second round with a failure to feed.
The Magpul D-50 GL9 pistol drum worked well and, despite the warnings from the company, did so without modifications or updates to our stock test pistols. However-- and to be fair this applies to every pistol drum-- it is awkward and heavy. Also, with an asking price of around $125, it is kind of spendy for what it is. Further, it will not fit in any mag carrier we had on hand.
When comparing apples to oranges with Glock factory 33-round sticks, of which you can easily buy three or four for the same cost as a single drum, the sticks may be a better option for most who want an extended capacity option.
Pros & Cons
We found it dependable in testing on stock Glocks with no mods.
Lots of fun on the range.
Probably the best Glock pistol drum in terms of dependability.
Easy to load.
It is heavy, at over a pound empty and more than two pounds loaded.
Magpul warns you may have to change mag releases and or springs on your Glock to get it to run reliably.
Good luck finding a mag pouch.
Cost is over $100.
Still, for those who have long looked for a reliable Glock-pattern pistol drum, or have a SUB2000 with the same desire, Magpul could just have the answer.