Four (and a half) types of magazines?

Knowledgeable Glock shooters look at Glock magazines in two categories -- original and drop-free.

Unfortunately there are actually four major categories, with numerous variations within each. The major categories are differentiated by mag capacity, drop-free characteristics, and floorplate design. The minor categories by metal finish: parkerized, nickel, "dark," and gold anodized (very rare).

	Original G17 "non-drop-free" The standard "non-drop-free" magazine originally issued with the Glock 17 can be identified by looking at the floorplate, and the back of the feed lips. The standard mag has a one-piece floorplate with "Glock" emblazoned on it -- but without any accompanying part number. Likewise the magazine tube was not originally identified by caliber (they only made one gun back then). This magazine was sometimes issued with the ill-fated "+2" floorplate, which was found to be less reliable, and prone to popping off when dropped or bumped against something. The cut-out behind the feed lips that surrounds the primer on the uppermost round in the magazine is U-shaped, as with other "non-drop-free" magazines. The metal parts of this magazine actually come in several of the four variations I mentioned above: nickel, "dark," parkerized, and according to the staff at Aro-Tek, there is a gold-anodized variant out there somewhere.
	Transitional G22 "non-drop-free" Original to the production G22, the transitional pattern can be found in 9mm, .40 S&W, 10mm, and .45 ACP, with "dark" and nickel metal finishes. Like the "standard" magazine, the cut-out behind the feed lips is U-shaped, and these mags have the signature stay-in-the-gun-when-loaded feature of the originals. (If you're new to Glockdom, when you press the magazine release with this magazine in place, it will not fall out of the gun if you have more than four rounds remaining. Hence the phrase "non-drop-free.") They differ primarily in the floorplate, which has a part number, and comes in two parts -- the floorplate itself, and the locking sub-floorplate found on modern Glock magazines. This plate appears to stay on better in recoil, and particularly when dropped onto a hard surface. The caliber will also be emblazoned on the back of the magazine tube: "9mm," ".40," etc.
	"New" law enforcement and pre-ban G17/22 "drop-free" Easily identified by its high magazine capacity and square-cornered cut-out behind the feed lips, the new high capacity "drop-free" magazine is considered the most reliable of the bunch. Unlike the originals, the "drop-free" magazine should fall out of the gun when the magazine released is pressed, no matter how many rounds remain in the magazine. To accomplish this, Glock uses a metal liner that surrounds the inside of the magazine tube except for the last half an inch. The drop-frees all use the locking floorplate, but this floorplate carries a separate part number and is dimensionally quite different from the transitional pattern. The newest law-enforcement mags have "For Law Enforcement Only" emblazoned on the back of the magazine tube, but are essentially identical to the pre-ban drop-free mags.
	New-Taper Drop-Free Without much fanfare, Glock released a new magazine body to go with their new "mod 5" and "mod 6" follower. By adding a small plastic shelf inside the mag tube, they ensured the old followers would not feed the last round 100%. We're having some fits getting the "Mod5 and Mod 6" followers to work in concert with our floorplates -- a most un-welcome surprise! A fix is in the works, but it's a little way off. Stay tuned for the latest.
	10-round magazines Incorporating the features of the drop-free mags, the 10-round magazines look almost identical to the pre-ban drop-frees, but go to various lengths to reduce their magazine capacity. The general strategy employed by Glock is to create a bulge running along the inside of the magazine walls, narrowing the internal dimensions considerably. This neccessitates a different spring and follower, but Glock changed the floorplate dimensions as well (Taylor Freelance mag extensions are designed NOT work on these magazines, and attempting to use such an extension is a violation of law). Follower design varies to fit the new inside dimensions, and in the new G17 mags, the follower itself has been re-shaped. The new follower is essentially flat, except for a significant bump that takes up the back half of the follower, rising under the rim of the bottom cartridge.