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.

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.