One of the beautiful things about Glock's G-series handguns is that factory replacement magazines are both affordable and readily available. Standard-sized factory mags can be had for as low as $25. For those who like to play around with a larger capacity, there are always extended capacity mags.
Why an extended capacity magazine
Extended magazines, extra-large capacity box devices that protrude below the normal grip of the pistol, look funny but offer a boost of firepower at your fingertips. In some cases, these magazines can almost double the capacity of the pistol. These extra rounds are imminently faster into the fight than any reload and allow the user to engage more targets before having to switch magazines. This can come in handy at the range or when in a combat situation.
The full-auto select-fire Glock 18 was designed to take an extended 33-round magazine from the outset. This magazine was copied by the Scherer Company and sold extensively since the 1980s for the Glock 17, 19, 26, and 34 to carry 33-shots of 9x19mm Parabellum. When they first came out, they ran for as low as $19. During the Assault Weapons Ban, their cost shot up to as much as $100. Overall, they worked but were sometimes finicky and hard to load. Scherer developed and marketed a 25rd .45acp mag for the Glock 21 series flame-spitter but it was not as well received as the 9mm version and many had reported hiccups with the stick.
Scherer also long-marketed a series of magazine extensions. Replacing the bottom floorplate of a standard or aftermarket magazine, these extensions could add a fingertip bulge to the base of the mag that held an extra two rounds of ammunition to the overall capacity.
On the outrageous side, Beta offered a version of the C-MAG for the Glock 9mm platform that holds 100-round in a pair of snail drums. Before you rush out for one, keep in mind, they run about $400.
Glock for years only offered flush-fitting standard capacity magazines with their pistols. During the dreaded 1994-2004 Assault Weapon Ban, these were limited to 10-round capacity to comply with Federal Regulations. It was during this time that the reign of the aftermarket extended capacity Shearer 33's for pre-ban weapons was firmly established. After the ban sunsetted without an extension due to a republican congress and white house, Glock examined releasing their own factory long stick mags and decided to proceed with filling the public demand.
Today they offer a 33-round 9mm, originally offered for the Glock 18, but will also fit the Glock 17 and 19 and a 22-round .40 S&W magazine for the Glock 22 and the compact 23 and 27. The .40 mag will also work with the .357SIG caliber G31/32/33 pistol although they are not marked for it due to the interchangeability of the rounds involved. These factory mags are a little more expensive than the aftermarkets at about $45-50 and are sometimes hard to find. However many the extra hunt and extra coin feel is worth it.
Downside of extended mags
Even with the above in mind, for many the good points outweigh the bad
- These mags are long. In most cases over 7-inches in length and hang out of the grip of even a full sized pistol a good 3-4 inches in some instances. This makes these mags impractical for CCW carry and keeps them firmly in the closet for range, home defense, and SHTF uses.
- Even with the end of the AWB, these are still not legal everywhere in the US. Notably, California, Cook County Illinois, Hawaii, Maryland, Massachusetts, New York, New Jersey, and DC all have laws banning their sale in those areas.
- With most of these the spring pressure is so great that usually even those with super thumbs will need to turn to a loader device to load the last few rounds to get the full capacity out of these mags.