Bought A Masterpiece Arms 930T & Sten Mags Won't Fit?

adn258 · April 20, 2020, 03:06 PM

Hey everyone, so I got a MPA930T recently which is their top cocking model. I absolutely love it! It's basically a Mac-10 style firearm with a fake suppressor that comes with it. It's a range toy, but it's a ton of fun. It comes with one polymer magazine.

Everywhere I looked online people have stated that the old metal 9mm sten magazines WILL WORK with Masterpiece's 9mm Mac-style handguns, including on other forums where people contacted Masterpiece arms directly. I got the 32 round 9mm sten mags. The mags look identical to the magazine I have, except for the fact that the old metal ones have some sort of metal adapter on the top which makes the magazine fatter.

You can see the images below. In the one where you see the metal mag in he gun I couldn't jam it in any further, and it wasn't locked in place. What am I missing here if anything? Can that metal part of these magazines be removed? Any help is appreciated guys as you are the best here!

Images Of Magazines And Gun In Links Below:

https://i.imgur.com/NgNZDgL.jpg

https://i.imgur.com/juTIkKq.jpg

Willie Lowman · April 21, 2020, 09:33 AM

Holy crap! Resize your photo! That's way too big

adn258 · April 21, 2020, 02:50 PM

I see that! I'm really sorry about that by the way, and I have no idea why it decided to become that large. I'm trying to find a way to edit my post but I'm not seeing it for some reason? Maybe a site admin can resize that or help me do it?

EDIT I finally figured out where the edit button was way over to the right! My apologies about that again. I just made the images hyperlinks which appear much smaller! EDIT

I called Masterpiece Arms and left a message yesterday. We'll see what they say when and if they call me back!

**44 AMP** · April 24, 2020, 12:59 PM

People on the internet saying something "will work" MUST be true, cause its on the Internet, right?

Unless the maker says (to you) in print that "X will work in our gun" then its all hearsay. Maybe it will, maybe it won't.

Did those people on the net say the mags will work, without any "modifications"?

That "extra metal" on the Sten mag is there so it fits and works in the gun it was designed for.

Also there is the question of the Sten mags you have might not be the "Sten mags" that other people had that worked.

Here's an example, I had a semi auto Tommy gun. GI tommy gun mags would not work in it, until they had been modified, then they worked fine. However, modifiying them to work in my gun meant they would no longer work in a full auto tommygun.

Around 30 years ago I had one of the MAC 10 type pistols, looked very similar to yours, mine said COBRAY on it. Had the polymer mags. Never had an issue with them. As a "spray and pray" -plinker it was fun, as a pistol trying to hit a target, it sucked.

There are 3 things you need to look at with those sten mags and your gun. First is what is it about the mag keeps it from going in far enough. Second, is if/when it goes in far enough, will it lock in, at the right place. Is there even a hole on the mag in about the right spot for the catch on your gun to engage??

And the third thing is only after the first two are solved, and that is, with the sten mag locked in at the "right" place, will it FEED??

Any time you are trying to use any magazine that wasn't originally designed for the gun you want to use it in, there can be a lot of issues. Most can be overcome with some work. Some take more work than others. Up to you to decide if its worth it, or not.

dakota.potts · April 24, 2020, 01:23 PM

Did you call or e-mail MPA? Now might be a hard time to get through to somebody, but I would try regardless.

Doing some reading, I can't find official corroboration anywhere that they currently accept steel STEN magazines. I did find a neat article on gunmagwarehouse about how and why they were originally designed to use Sten mags because of AWB restrictions. That same article indicated that Tapco designed dual-use magazines for a while that fit the MPA and the Sten, and the way it was worded seemed to imply that maybe the newer models of MPA were designed to fit this specific polymer magazine. MPA's product listing for the magazine also notes that their 30-round polymer magazines may require fitting in some older models of the Defender series.

Put together, this leads me to believe there might be some minor variance in the line as it progressed over the years. My gut says there's a 50/50 chance the Sten mag will work fine with just minor fitting. My head says the right thing to do is call the manufacturer and get the official word. MPA's a great company, they should get you taken care of.

adn258 · May 4, 2020, 04:13 PM

dakota.potts Thanks for everyone's help. I contacted a guy at MPA. He was very nice, and is their tech support gunsmith/manufacturing guy. He said they used to use Sten Mags in 9mm for past guns. The reason they switched to their own polymer magazines is because he said almost ALWAYS they got sten mags that needed some modifications to work. He told me they "technically work now and should lock into place", but that usually they need to be worked on before this happens.

He told me the steel would get bent etc. and that it needed sanding and modification in spots. Give the fact I have 3 of them, I see where it's rubbing. My guess is they might work with modifications. I'm thinking of whether or not that's worth it to me when I can just buy polymer magazines that have a 100% chance of working for 25 bucks.

I feel like the sten mags are a good collectible item in all cases.

**44 AMP** · May 6, 2020, 12:41 AM

Somewhere out there are guys who would just love unmodified sten gun mags. They MIGHT even be willing to pay you what you paid for them...

A few years ago I sold several GI 30rnd Tommy gun stick, some in the original wrap, that I had not gotten around to modifying to fit my semi auto. Due to the fact that I had sat on them for a decade or more, I was happy to accept the dealer's offer, which was slightly below current market, but well above what I had paid.

I'd say get new mags that will work without mods, and recoup what you can from the Sten gun mags. Your call.

jetinteriorguy · May 7, 2020, 05:32 PM

For the right price I might be that guy.

smee78 · May 12, 2020, 12:08 PM

I have an older model MPA and it works fine with most Sten mags. Every once in a while I found one that needed minor modification to work. A few minutes with a file at the mag catch was what most of them needed for mine. YMMV

ProjectCamaro · May 28, 2020, 10:44 PM

I have one that I bought probably 10-15 years ago at this point. The Sten magazines work perfectly in it. I bought a bunch, several in really bad shape and with minimal cleaning they were all able to work.

I'm wondering if there's been a change in the design by MPA that as a consequence of it means they'll no longer work.

**Aguila Blanca** · May 29, 2020, 12:01 AM

Quote:

Originally Posted by adn258

He told me they "technically work now and should lock into place", but that usually they need to be worked on before this happens.

I'm sorry, but to me that translates as "They technically should work now except that they don't work."

Doublespeak is doublespeak. Either something works ... or it doesn't. If something needs to be "worked on" before it works ... it doesn't work.

April 20, 2020, 03:06 PM	#1
adn258 Senior Member Join Date: May 12, 2010 Location: Montana Posts: 121	Bought A Masterpiece Arms 930T & Sten Mags Won't Fit? Hey everyone, so I got a MPA930T recently which is their top cocking model. I absolutely love it! It's basically a Mac-10 style firearm with a fake suppressor that comes with it. It's a range toy, but it's a ton of fun. It comes with one polymer magazine. Everywhere I looked online people have stated that the old metal 9mm sten magazines WILL WORK with Masterpiece's 9mm Mac-style handguns, including on other forums where people contacted Masterpiece arms directly. I got the 32 round 9mm sten mags. The mags look identical to the magazine I have, except for the fact that the old metal ones have some sort of metal adapter on the top which makes the magazine fatter. You can see the images below. In the one where you see the metal mag in he gun I couldn't jam it in any further, and it wasn't locked in place. What am I missing here if anything? Can that metal part of these magazines be removed? Any help is appreciated guys as you are the best here! Images Of Magazines And Gun In Links Below: https://i.imgur.com/NgNZDgL.jpg https://i.imgur.com/juTIkKq.jpg Last edited by adn258; April 21, 2020 at 02:56 PM.

April 21, 2020, 09:33 AM	#2
Willie Lowman Senior Member Join Date: March 5, 2009 Location: Uh-Hi-O Posts: 3,006	Holy crap! Resize your photo! That's way too big __________________ "9mm has a very long history of being a pointy little bullet moving quickly" --Sevens

April 24, 2020, 12:59 PM	#4
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,844	People on the internet saying something "will work" MUST be true, cause its on the Internet, right? Unless the maker says (to you) in print that "X will work in our gun" then its all hearsay. Maybe it will, maybe it won't. Did those people on the net say the mags will work, without any "modifications"? That "extra metal" on the Sten mag is there so it fits and works in the gun it was designed for. Also there is the question of the Sten mags you have might not be the "Sten mags" that other people had that worked. Here's an example, I had a semi auto Tommy gun. GI tommy gun mags would not work in it, until they had been modified, then they worked fine. However, modifiying them to work in my gun meant they would no longer work in a full auto tommygun. Around 30 years ago I had one of the MAC 10 type pistols, looked very similar to yours, mine said COBRAY on it. Had the polymer mags. Never had an issue with them. As a "spray and pray" -plinker it was fun, as a pistol trying to hit a target, it sucked. There are 3 things you need to look at with those sten mags and your gun. First is what is it about the mag keeps it from going in far enough. Second, is if/when it goes in far enough, will it lock in, at the right place. Is there even a hole on the mag in about the right spot for the catch on your gun to engage?? And the third thing is only after the first two are solved, and that is, with the sten mag locked in at the "right" place, will it FEED?? Any time you are trying to use any magazine that wasn't originally designed for the gun you want to use it in, there can be a lot of issues. Most can be overcome with some work. Some take more work than others. Up to you to decide if its worth it, or not. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

April 24, 2020, 01:23 PM	#5
dakota.potts Senior Member Join Date: February 25, 2013 Location: Keystone Heights, Florida Posts: 3,084	Did you call or e-mail MPA? Now might be a hard time to get through to somebody, but I would try regardless. Doing some reading, I can't find official corroboration anywhere that they currently accept steel STEN magazines. I did find a neat article on gunmagwarehouse about how and why they were originally designed to use Sten mags because of AWB restrictions. That same article indicated that Tapco designed dual-use magazines for a while that fit the MPA and the Sten, and the way it was worded seemed to imply that maybe the newer models of MPA were designed to fit this specific polymer magazine. MPA's product listing for the magazine also notes that their 30-round polymer magazines may require fitting in some older models of the Defender series. Put together, this leads me to believe there might be some minor variance in the line as it progressed over the years. My gut says there's a 50/50 chance the Sten mag will work fine with just minor fitting. My head says the right thing to do is call the manufacturer and get the official word. MPA's a great company, they should get you taken care of. __________________ Certified Gunsmith (On Hiatus) Certified Armorer - H&K and Glock Among Others You can find my writings at my website, pottsprecision.com.

May 6, 2020, 12:41 AM	#7
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,844	Somewhere out there are guys who would just love unmodified sten gun mags. They MIGHT even be willing to pay you what you paid for them... A few years ago I sold several GI 30rnd Tommy gun stick, some in the original wrap, that I had not gotten around to modifying to fit my semi auto. Due to the fact that I had sat on them for a decade or more, I was happy to accept the dealer's offer, which was slightly below current market, but well above what I had paid. I'd say get new mags that will work without mods, and recoup what you can from the Sten gun mags. Your call. __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

April 21, 2020, 02:50 PM	#3
adn258 Senior Member Join Date: May 12, 2010 Location: Montana Posts: 121	I see that! I'm really sorry about that by the way, and I have no idea why it decided to become that large. I'm trying to find a way to edit my post but I'm not seeing it for some reason? Maybe a site admin can resize that or help me do it? EDIT I finally figured out where the edit button was way over to the right! My apologies about that again. I just made the images hyperlinks which appear much smaller! EDIT I called Masterpiece Arms and left a message yesterday. We'll see what they say when and if they call me back!

May 4, 2020, 04:13 PM	#6
adn258 Senior Member Join Date: May 12, 2010 Location: Montana Posts: 121	dakota.potts Thanks for everyone's help. I contacted a guy at MPA. He was very nice, and is their tech support gunsmith/manufacturing guy. He said they used to use Sten Mags in 9mm for past guns. The reason they switched to their own polymer magazines is because he said almost ALWAYS they got sten mags that needed some modifications to work. He told me they "technically work now and should lock into place", but that usually they need to be worked on before this happens. He told me the steel would get bent etc. and that it needed sanding and modification in spots. Give the fact I have 3 of them, I see where it's rubbing. My guess is they might work with modifications. I'm thinking of whether or not that's worth it to me when I can just buy polymer magazines that have a 100% chance of working for 25 bucks. I feel like the sten mags are a good collectible item in all cases.

May 7, 2020, 05:32 PM	#8
jetinteriorguy Senior Member Join Date: April 28, 2013 Posts: 3,176	For the right price I might be that guy.

May 12, 2020, 12:08 PM	#9
smee78 Senior Member Join Date: July 14, 2008 Location: South Carolina Posts: 2,918	I have an older model MPA and it works fine with most Sten mags. Every once in a while I found one that needed minor modification to work. A few minutes with a file at the mag catch was what most of them needed for mine. YMMV __________________ We know exactly where one cow with Mad-cow-disease is located, among the millions and millions of cows in America, but we haven't got a clue where thousands of illegal immigrants and terrorists are

May 28, 2020, 10:44 PM	#10
ProjectCamaro Senior Member Join Date: July 27, 2009 Location: Wisconsin Posts: 230	I have one that I bought probably 10-15 years ago at this point. The Sten magazines work perfectly in it. I bought a bunch, several in really bad shape and with minimal cleaning they were all able to work. I'm wondering if there's been a change in the design by MPA that as a consequence of it means they'll no longer work.