As another member posted, .45's can be shot successfully in a 9mm STEN mag.  I took Bill's advice and did some minor mods on the feed lips, just by spreading them apart enough to match my .45 Uzi Oly-converted mags.  I tested it out today with both 185gr JHP reloads and also some cast 225gr LRN bullets from a Lyman mould seated a little deeper to fit in the STEN mag.  The JHP's misfed once, but the cast bullets fed 100%.

I'll be doing more extensive testing soon, but I just wanted to post this success now.  It's sure a lot cheaper to get a SOCOM mag block and cheap STEN mags than it is to buy a lower and more expensive Grease Gun mags.

Um.....yes.  Post pics and make this post worthwhile, please.

How did you spread the lips?

Quoted: How did you spread the lips?

Here's my video of .45 ACP in a Sten mag. 185gr Sabre HPs. Spread the feed lips with a pair of pliers. It will break the weld on the back a little but it works ok even if you don't reweld the cracks.

www.youtube.com/watch?v=8es1gCrjkUQ

I have 5 rnd and 20 rnd Sten mags for 7.62Tok, that I made by shortening them and removing the rib in the back of the mag body.  I don't have a .45 upper, but I checked and the mags will hold 230gr FMJ .45acp with room to spare.  The 20 rnd mag is just a hair too short for 10 rnds of .45, and the 5 rnd mag holds 3.

I use an SNS block.  It's available (or was, earlier this year) with a slot for a 9mm ejector.  Leave the ejector out, and it works with Oly uppers and gas uppers.  Install the ejector, and it works with Colt style 9mm uppers.

Quoted: Um.....yes.  Post pics and make this post worthwhile, please.

Umm.....I'm really concerned with getting your approval of what is a "worthwhile" post.

Anyway, as mentioned by someone else, just spread the feed lips apart just enough to match up with the feed lips of a .45acp magazine.  It does break the welds on the rear corners, but after more testing, I'm just going to TIG them in place, not that they aren't heavy enough to stay in place the way they are.

It's pretty self explanatory, but if you really need a pic showing the feed lips opened up about .015" on each side, I guess I can post a pic for you.  It is easy though, just match them up to the mag you already use and it will put the top round right where it has to be for the bolt to strip it out.

I hope you have found this information to be worthwhile!

The STEN mags just need the lips opened up a bit to use 45 ACP, huh?
I am just getting into the pistol cal AR game so my knowledge is limited in this field.
Could the same thing be done with the 9mm beta drum?
Sorry if this is an old and crusty topic, but I really feel the need to get one of Oly's short pistol upper in 45 and then try to find a usefull mag somewhere else.

The proble with drums is the space the rounds ride in is usually a curved slot that matches the curve of the brass case. .45rds will not fit in those drums that use this slotted feed mechanism as the brass is much fatter than 9mm. And a reminder OAL is the key factor. You must use flat tip or HP .45 bullets to keep the OAL short enough to fit in a 9mm Mag.

TC, can you do this with 9mm uzi mags as well? HP and flat tip .45 ammo? I've got my gg mags waiting, but just looking at all other alternatives.

sorry for the hijack!

It should definitely work for any straight 9mm magazine. The only issue I see is some 9mm mags are made of thin metal and the feed lips tends to spread too much from the force of the .45 rds. The Sten work great because of the double thickness feed lips.

what would keep you from milling or grinding out the .015 from the inside of the mags to creat the clearance?

I have something like 40 sten mags and an extra lower.  Plus I have over 5k of 45s sitiing around.

Also what style convesions are there available in .45?  I have always wanted one.  

please advise.

thanks Jim

You could always weld a new back on the STEN mag after removing the groove in the rear, which would give you all the needed clearance.  But, if you plan to use the SOCOM mag block, you need the groove for the paddle release to grab.  I've never used any of the other mag blocks, so I can't comment on that.  

I'm planning to try out another bullet mould for my .45acp.  I have a Lee .45LC mould which is a cowboy-type RNFP in 250gr weight.  The Lee reloading manual gives loading data for that bullet weight in a .45acp, so I'll experiment with that some.

I'm ordering 50 STEN mags next week so I can convert a few of them for the .45LC and set the rest aside.  I'll keep some stock and, hopefully, I'll get a .40 upper sometime and alter the feed lips for that caliber.  

If you do attempt to remove the groove from the rear of a STEN mag, please post pics if it's successful.  I'd be very interested.

Quoted: If you do attempt to remove the groove from the rear of a STEN mag, please post pics if it's successful.  I'd be very interested.

This one worked until I goofed and made the cut for the magcatch a little too deep (cut through the internal rib in the side of the mag, so the rounds hang up in the notch).



This one worked (didn't cut too deep when I made the cut for the magcatch), and I welded a scrap strip, from a mag that didn't work, to the back to close the open slot.  The mag worked with the back open, but I was a bit concerned about the primers being exposed.

In the lower section (below the reinforced top section), the rib can be removed with a dremel and the reinforced cutting wheels.  To remove the rib in the reinforced section at the top, I put the mag in a vice with the front of the mag facing upward, then used a hacksaw (slipped the blade through the mag, then reattached it to the hacksaw frame) to carefully cut a groove on either side of the rib.  Once the groove is nearly all the way through the inner layer of the top of the mag, it can be broken out with a screwdriver or other suitable prying tool.  It took a few tries to get it right, but it's doable with simple tools and a little patience.

I've mainly been cutting them down to a 20 round length, before removing the rib, since it makes the hacksaw work a little easier.


ETA:  Both of those mags loaded with .45acp.  The feedlips haven't been opened up, so the top round sits very low.

what would keep you from milling or grinding out the .015 from the inside of the mags to creat the clearance? I have something like 40 sten mags and an extra lower. Plus I have over 5k of 45s sitiing around. Also what style convesions are there available in .45? I have always wanted one. please advise. thanks Jim

Here is a thread listing the current .45 conversion options.
www.ar15.com/forums/topic.html?b=3&f=15&t=301130

The only thing keeping someone from milling out the extra material is the skill and equipment to do so. I've been taking a lot of time looking for .45 options that use existing parts with little to no modification for the guy that doesn't have too much money.

JPN-What mag block are you using?  It just seems like the SOCOM mag catch won't have anything to stop on and will push against the rounds.

I have access to milling machines, so if the mag catch issue could be resolved, this wouldn't be a bad idea.

Thanks for posting the pics.

Quoted: JPN-What mag block are you using?  It just seems like the SOCOM mag catch won't have anything to stop on and will push against the rounds. I have access to milling machines, so if the mag catch issue could be resolved, this wouldn't be a bad idea. Thanks for posting the pics.

SNS magblock.  It's listed near the bottom of their price list.  

It requires cutting a shallow notch in the side of the Sten mag, to work with the AR magcatch.

If I'm not mistaken, they make a version with a slot for a RRA 9mm ejector, and a version without the ejector slot (the no slot version works with Oly uppers, the slot version can be used with either Oly or colt style uppers).  My only complaint has been with how long I had to wait to receive it, so I'd suggest emailing and asking if they have them in stock, before ordering.  My first one worked so well (with 7.62Tok upper using a standard bolt carrier assembly and shortened gas system), that I now have three - one has an ejector and is waiting for funds to complete a colt style 9mm upper, the other is being modified to use CZ24 mags.

Here's a picture of the CZ24 setup.



The feedramp is not installed (still need to trim it to clear the mag), and I have to cut a couple of notches in the upper receiver for clearance.  The CZ mag needed a little file work on the back corners to fit the lower, and it's just too wide for the upper - the mag sits about a 1/4" too low, with an unmodified upper installed.


ETA: And here's a picture of the unmodified SNS block(with RRA ejector installed), with my modified Sten mag (rib removed from the back) and 230gr FMJ .45acp.