I ordered 2 of the 20 round mags. After jam after jam asc and c products I decided to spend a little more and try 2 of these. I was happy how well built they are and they actually hold 24 rounds. I loaded them up and let them go. The do activate the hold open and function perfectly.

These are worth the money, and have been incident free since I began buying them. Reload them with the "ProMag Magazine Loader Colt SMG, AR-15 9mm Luger 5-Round Polymer Black"--5 rounds at a time, which is effortless.

As the headline says, these magazines fit and work great and the finish is fine. They appear very well made and are smoothly finished. So far they have worked perfectly with my YHM 9mm conversion kit. The springs are very stout so you may want to save your fingers and purchase a loading tool.

Very reliable with both FMJ/JHP 124gr 9mm ammo in my dedicated 9mm AR (no magblock).

Only downside is they are tough to load. Invest in a Lula mag loader

i run these in my DDLES lower with CMMG upper. never had one problem, but have had problems with c-products not feeding. there's a substantial difference in quality between these and the c-products. one hint: BUY A MAGLULA COLT SMG LOADER...save your thumbs so you can give Brownells a "thumbs up".

I run a Rock River Arms 9mm upper with a Hahn bottom-load magazine block. I run an RRA 9mm buffer with 8 quarters in the buffer tube to act as as spacer. Recoil spring is a fresh Brownells AR carbine spring.

The Metalform magazines with the metal Uzi-type followers work the best for me. The C-Products/new-Colt magazines feed okay, but don't lock the bolt open very reliably. The Metalform magazines with polymer followers are a little better than the C-Products magazines, but still don't lock the bolt open 100% of the time.

The polymer ProMag/Bushmaster mags are okay for plinking or general blasting, but they aren't even as good as the C-Products magazines.

The only issue is that, with my upper/lower set-up anyway, the magazines need a little bit of a break-in. The rifle has a hard time stripping the first two rounds from a new, fully-loaded magazine. Download to 30 rounds for a while, and after a few uses they're good to go.

Finish varies, from batch to batch, but I think they are all black, and the finish will likely outlast any C-Products magazine, which will be scratched down to bare metal after the first use.

Although I can't promise 100% flawless performance, the new Metalform magazines seem to be your best bet.

I have two Colt L/E AR 9mm. These are the only mags that will load with the bolt closed (tac-reload) You will have to push a little harder than with standard 5.56 mags. They will also lock the bolt back everytime in a Colt AR-15. I have also run C-mags but not any more. These are the same as the old (ban,preban)Colt mags. I have both.

Mags work great run perfect in my Colt SMG and factory SBR Rock River 9mm AR!! Has a very strong spring the Lula mag loader makes loading the mags essy...

I purchased 3 of the magazine from Brownells. None of them worked smoothly in my Colt 9MM SMG'S. The bolt would have to be locked back to insert the loaded magazine, The bolt release was so tight it took two thumbs to release the bolt, The finish stated was oxide, But they were polished blue. The new magazines from Metal Form are no comparison to my pre ban factory colt magazines!! And the C-Mags work perfectly with my Colt 9MM SMG'S..

I had perpetual feeding problems with a carbine built with a Bushmaster lower, RRA upper, and Hahn Precision dedicated magazine block until I switched to Metalform magazines. The channel that the magazine bolt release tab rides in is extremely clean. The magazine bodies are thicker, well finished and do not rattle when locked into position. The followers are metal, and the magazine springs hold up better than ones now found in new Colt-oem magazines.

Metalform was the OEM for Colt's on SMG / 9mm AR15 magazines before they foolishly went with C-Products. They are still the best and work reliably. If your gun has a bolt hold open, these are the most likely to work properly without modification.

I run these in a Spike's Tactical upper / RRA lower with Hahn magazine block. I own both Metalform and C-Products magazines, the MF are hands down superior in terms of quality and materials. I purchased mine elsewhere last year before Brownells wisely started selling them.

The Metalforms stand the best chance of working with your bolt hold open, if your gun has one. The C-Prod mags required follower modification but now run fine, even the "new and improved" follower units. Your mileage may vary, but my experience seems to be the norm with these.

Don't buy these if you have an Olympic Arms 9mm AR, as these are only for guns using the original Colt's system such as RRA and Spike's Tactical.

Do yourself a favor, buy a Colt SMG Maglula if you use these. Like the Uzi mags they were based on, the Metalform 9mm magazines can be a female dog to load! You don't want your thumb to turn black and fall off after loading the second mag. :^) The Maglula is Brownells 593-000-044.

One other possible negative I've read about, but never experienced, is these magazines can turn into ammo fountains and simultaneously vomit out their entire payload if mishandled, dropped, or misloaded. Never had this happen to me, but this and the hard-to-load gripe are the most common complaints. That's not a criticism of Metalform, but of the Colt 9mm SMG magazine design.

Keep your powder dry and good shooting!!!