View Full Version : AR 15 9mm mags hard to remove

Vulcan Classic
October 29, 2009, 04:35 PM
I just bought a Bushmaster AR, with a colt upper & a colt style mag block. Two 25 round steel mags came with the rifle. The only markings on the 2 mags are "S4" on one side & "IMI" on the other. Can anyone tell me anything about the mags?
Also both mags fit real tight. To extract them you have to hold with a full hand and pull fairly hard. This is true with a full mag or empty.
I also just bought three 32 round pro mags. They will extract with a two finger pull, when empty, but when loaded it takes a good grip and a fairly hard pull.
My question is this: Should I take the block out and so some filing to make more room, or is this normal for the 9mm?


October 29, 2009, 04:52 PM
IMI is Israel Military Industries, makers of the Uzi and other fine products.

Vulcan Classic
October 29, 2009, 04:57 PM
OK, time for a dumb question, why is IMI making a 9mm for a colt style mag block? Is colt & UZI the same style??

October 29, 2009, 05:04 PM
Uzi Magazines can be easily modified to work with the Colt Style 9mm upper. That is, you need to mill out a magazine catch on the correct position, as well as sometimes needing to mill down the back of the magazine for bolt clearance. Once modified, the magazine can easily be used in either the AR 9mm or Uzi. It doesn't adversely effect the magazine.

It's pretty common in the 9mm AR world to use cheap bulk Uzi Mags to feed "Colt Style" ar's. (Includes Rock River Arms)

The "Other" type is the single feed magazine. They tend to use Sten Mags for cheap feeding. (Olympic Arms)

Both the Colt style and Olympic arms style AR 9mm conversions can be had with a Mag Well Insert to use the correct 9mm magazines.

There is a THIRD type that is coming around using GLOCK 18 Magazines. So far Olympic Arms makes a complete rifle (Will not sell just the lower) and Lone Wolf Distributers is now making a Glock Only lower. These can not easily be converted from one caliber to the other. (The magazine catch on the Glock Magazines is not easily compatible with the AR magazine relase.)

There is a company that makes magazine wells SEPARATE from their lowers, but I can't recall the name off the top of my head.

I have a couple Lone Wolf Dist. Glock only Lowers on back order. I plan to build a couple dedicated 9mm Rifles for multi gun matches and plinking.

As far as the magazines being "difficult" to extract, that's not unusual. The Mag Block usually is a bit tight and will loosen up a bit with use. ;)

Vulcan Classic
October 29, 2009, 05:13 PM
Thanks a bunch. You know your mags. What about the "sticking" issue? Should I relieve/file on the block insert?

October 29, 2009, 05:15 PM
The block inserts are usually aluminum. They are usually a bit tight when they are new. As you use it, it will loosen up. The steel mags will "break in" the well insert. Don't fret. Just shoot and enjoy. ;)

A lot of the IMI mags are military surplus. If the lips are bowed out a bit, you can sometimes "coax" them back into place.

October 29, 2009, 05:16 PM
Since you already have found magazines that work well I'd put the other two on gunbroker and NOT modify the rifle.

October 29, 2009, 05:17 PM
If you're using a Busy LOWER, make sure the hammer doesn't have a little HOOK ON IT. The Rock River Hammer, or DPMS Hammer is a better choice with the 9mm conversions. They aren't so rough on the hammer pin. The ramped hammers can hang up on the 9mm bolt if the bolt isn't ramped.

Vulcan Classic
October 29, 2009, 05:47 PM
Joined this outfit 7 days ago. Had a Remington 1100 problem & this 9mm mag problem. Both issues were quickly addressed. Thanks to all.