Thought I would start the talk on the new mags from ETS. There are a couple of things that they have over the Magpul mags IMO.
-Able to use any Glock OEM baseplate, or aftermarket baseplate/mag extension.
-Factroy 140mm USPSA/Multi-gun legal mag.

The other arguables that give it a potential leg up are that its translucent, and cheaper than an OEM mag; especially when considering buying mag extensions and an OEM mag. I have pre-ordered a couple standard G17 and 140mm mags from Rainier Arms (link below). Obviously a downside to using a 140mm factory mag is that you forgo the added weight that a mag extension adds and can aid in dropping free. If the mags seem durable and good to go, I might try adding some lead weights into the bottom. I'll have to see when they arrive. For a guy getting started into multi-gun I think they would be a good purchase. It will give you the added capacity to compete with fewer reloads, cost far less than the standard extended setup, work well as a USPSA Limited Division mag if you don't stick with it, or like to train in that discipline when there are no 3 Gun matches. They are releasing a standard capacity G19 and G17 mag along with the 140mm and 31 round magazines. Links below to the Rainier pre-order for the curious.

Glock 19 Standard
Glock 17 Standard
140mm Mag
Sub-gun/31 round mag

ETA Picture for the other kindergarten level readers like myself.

Very curious about these magazines.

I like the idea of being able to see the rounds, but I'm always worried about durability and function from a non factory magazine.

The cost is good, but if they don't work cost is out the door.

I would like to know what you think when you get them, give us the details when they arrive.

Will do, for sure. I'm the same way, but I'm sick of paying that much for pistol mags. The capacity is a necessity for the sport though IMO. I'm shocked to see this, but only because I really expected something like this from Magpul.

Anyone else notice that the mag is .50mm too long for Practical or Factory?

I'm wondering if that might be a misprint. It says they are USPSA legal, which would lead me to believe they meant to put in .25, not .75.

I emailed ETS, and they stated that they did misprint the numbers. The mag is actually 141.25mm. They stated they built it using the USPSA guage as a guide. The 31 round magazine was not built for USPSA so does not meet the 171.25mm rule though.

My detective skills tell me at least one of the 22 rounders will become immediately available to me on the 25th.  I'll let you guys know what I think of them.

Mine came in a couple of days ago. For full disclosure I am evaluating these as a potential replacement to OEM mags with extended basepads. Obviously the one thing you're definitely missing out on is weight. So far none of mine have dropped free while empty. I might shoot a little bit today, and will report back.

I shot 200+ rounds through these mags a few days ago. They seem to run pretty well. No malfunctions of any kind while using them. I ran drills that I would typically run which include everything from modified static El Pres, to dynamic movement drills. Reloads were typically done with at least a couple of rounds left in the mag. Mags dropped free every time, and really surprised me. I think when I first received them and was messing around with them I had the pistol of too much of an angle for a mag to drop free. I'll keep trying them and report back. Both of my brothers bought a couple as well to use in practice before the 3 Gun season gets in full swing here. I should have a fairly thorough test when I report back the next time including a close inspection and pictures of the mags after a couple thousand rounds.

I used one in a 3gun match down here in houston.  It failed to feed on a slide lock reload with the full 22 rounds.  I smacked the back of the slide and it went into battery.  I'll give it few more tries.  could have been a fluke.

I ran these mags exclusively at a 3-Gun match out in NC this past weekend. I was surprised to spot at least 5 more of the competitors running these mags. I myself had no malfunctions, and did not witness any from the other competitors on my squad running ETS mags. I did have to strip the mag on the first stage, but I again think it was more the angle I was holding the gun as I've had the problem with my Dawson baseplate Glock mags as well at times. I'll keep running them and report back.

I took a friend with me to shoot his first match of any discipline. He wanted to jump in with both feet so I offered to loan him the equipment. I let him load up my OEM mags with Daswson basepads so that way if the ETS mags shit the bed it would be on me and not him. Because of this I ran the ETS mags exclusively all day. It was around a 125 pistol round match (for me anyways ). Also, he ended up being interested in them as he does not own most of the gear for the sport and they are significantly cheaper than buying OEM's and basepads.

All three of my 22 rounders turned into rattle cans using the steel cased ammo.

I hate using brass at lost brass matches.

I've been using ETS magazines for Steel Challenge competition for the last two years.  They've been dropped in the dirt, kicked, stepped on and zero problems.  The first three I bought were used to practice with a new G-34.  6000K rounds in a couple of weeks proved their reliability.  Since the I've picked up 27 more and have yet to have a problem.