AR pistol with fixed Mag? (In mass )

jayhitek

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Oh, so you don't want to pin the mag for a max of 10 rounds. You're looking to permanently fix the mag in the lower to make it "MA Compliant".
I believe they make special mag non-release buttons for that.
 
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Oh, so you don't want to pin the mag for a max of 10 rounds. You're looking to permanently fix the mag in the lower to make it "MA Compliant".
I believe they make special mag non-release buttons for that.
Correct. The language of the law is somewhat open to interpretation about what is considered "permanently fixed". Even the MA lock from Mean Arms can be removed with hand tools. I'm on a waiting list for a Dark storm industry lower but since I have a lower that I can dock around with, I thought I would go ahead and scratch build one for knowledge.
 

mlaboss

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Correct. The language of the law is somewhat open to interpretation about what is considered "permanently fixed". Even the MA lock from Mean Arms can be removed with hand tools. I'm on a waiting list for a Dark storm industry lower but since I have a lower that I can dock around with, I thought I would go ahead and scratch build one for knowledge.

All you have to ask yourself is, would a MA court consider your gun able to "accept a detachable magazine", since that's what the law actually says.

It doesn't say anything about "permanently fixed" or "only removable with tools" or any of that nonsense. The key word is "detachable".

What does "detachable" mean? Your guess is as good as mine, but my guess is that if you can remove the magazine from the gun without damaging or destroying the gun or the magazine, then it is "detachable".
 

amm5061

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Correct. The language of the law is somewhat open to interpretation about what is considered "permanently fixed". Even the MA lock from Mean Arms can be removed with hand tools. I'm on a waiting list for a Dark storm industry lower but since I have a lower that I can dock around with, I thought I would go ahead and scratch build one for knowledge.

So I can tell you how the DSI lowers work, since I have one.

There is a set screw inside of the trigger pocket. A hole is drilled inside the trigger pocket into the magwell, and the set screw fixes the magazine in the magwell. There is no milled out location for a mag catch to be installed. There may be other fixed locations, but that's the only one I could find when I examined my lower.

To remove the pmag from the lower, you would need to either forceably rip it out, or remove the trigger and hammer assemblies, get an impossibly tiny allen key in there, and slowly, 1/8th of a turn by 1/8th of a turn, disengage the set screw. It would be a bitch to remove, and without a mag catch, they can't just slap in a post ban 30 rounder. They'd have to drill it in the right spot to engage with the set screw or the thing would just slip out. I don't believe friction would hold it in.
 
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So I can tell you how the DSI lowers work, since I have one.

There is a set screw inside of the trigger pocket. A hole is drilled inside the trigger pocket into the magwell, and the set screw fixes the magazine in the magwell. There is no milled out location for a mag catch to be installed. There may be other fixed locations, but that's the only one I could find when I examined my lower.

To remove the pmag from the lower, you would need to either forceably rip it out, or remove the trigger and hammer assemblies, get an impossibly tiny allen key in there, and slowly, 1/8th of a turn by 1/8th of a turn, disengage the set screw. It would be a bitch to remove, and without a mag catch, they can't just slap in a post ban 30 rounder. They'd have to drill it in the right spot to engage with the set screw or the thing would just slip out. I don't believe friction would hold it in.
Thank you for the information and taking the time to share it. That's interesting, I assumed they just milled a mag into the lower while manufacturing.
 

jayhitek

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So I can tell you how the DSI lowers work, since I have one.

There is a set screw inside of the trigger pocket. A hole is drilled inside the trigger pocket into the magwell, and the set screw fixes the magazine in the magwell. There is no milled out location for a mag catch to be installed. There may be other fixed locations, but that's the only one I could find when I examined my lower.

To remove the pmag from the lower, you would need to either forceably rip it out, or remove the trigger and hammer assemblies, get an impossibly tiny allen key in there, and slowly, 1/8th of a turn by 1/8th of a turn, disengage the set screw. It would be a bitch to remove, and without a mag catch, they can't just slap in a post ban 30 rounder. They'd have to drill it in the right spot to engage with the set screw or the thing would just slip out. I don't believe friction would hold it in.

To be fair, this is how one manufacturer handled this by building a lower from the ground up with a fixed magwell in mind. Companies like JC Arms handles it a totally different way. That seems a lot less complicated.. Using an already manufactured lower like the OP has.
 

pupchow

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To be fair, this is how one manufacturer handled this by building a lower from the ground up with a fixed magwell in mind. Companies like JC Arms handles it a totally different way. That seems a lot less complicated.. Using an already manufactured lower like the OP has.

For a $100, they'll swap it for a standard lower. "What happens if I move out of state? - DSI will swap the fixed magazine lower for a standard DS-15 lower for the ORIGINAL owner for $100 fee."

And if you did decided to SBR the thing?
 

amm5061

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For a $100, they'll swap it for a standard lower. "What happens if I move out of state? - DSI will swap the fixed magazine lower for a standard DS-15 lower for the ORIGINAL owner for $100 fee."

And if you did decided to SBR the thing?

Why the hell would you SBR it? Just use a regular lower for an SBR.
 

pupchow

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Why the hell would you SBR it? Just use a regular lower for an SBR.

In my case, I put together a fixed mag 9mm pistol (AR w/Endomag) for a specific reason. After doing a bit of plinking with it, and repeatedly having to break it open to top off the mag, I'd rather SBR it.
 

jayhitek

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In my case, I put together a fixed mag 9mm pistol (AR w/Endomag) for a specific reason. After doing a bit of plinking with it, and repeatedly having to break it open to top off the mag, I'd rather SBR it.
I believe once you've registered it as a pistol you cannot make it into a rifle.
You can go the other way through and change a rifle into a pistol.
 

amm5061

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In my case, I put together a fixed mag 9mm pistol (AR w/Endomag) for a specific reason. After doing a bit of plinking with it, and repeatedly having to break it open to top off the mag, I'd rather SBR it.

Okay, I think I understand now. You mean unfix the mag, then SBR it. All you're gonna do SBRing a fixed mag gun is pay $200 to create a situation that could've been avoided with a pistol brace, so I was very confused.
 

amm5061

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I believe once you've registered it as a pistol you cannot make it into a rifle.
You can go the other way through and change a rifle into a pistol.

You got that backwards my friend. You can go from pistol to rifle back to pistol if you want, but you cannot go rifle to pistol. That becomes an SBR according to the ATF.
 

Mountain

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Correct. The language of the law is somewhat open to interpretation about what is considered "permanently fixed". Even the MA lock from Mean Arms can be removed with hand tools. I'm on a waiting list for a Dark storm industry lower but since I have a lower that I can dock around with, I thought I would go ahead and scratch build one for knowledge.

If you install the MA lock properly, you'd be covered for Mass.
 
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Hey y’all I’m wondering if anyone has looked into converting a fixed 10 round pmag to shoot from a 9mm upper? Also been a member for a little while this is my first post. Thanks in advance y’all!
 

Viper22

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Hey y’all I’m wondering if anyone has looked into converting a fixed 10 round pmag to shoot from a 9mm upper? Also been a member for a little while this is my first post. Thanks in advance y’all!

Are you looking to convert an existing fixed mag lower?

Or looking to use a standard lower and build it as a 9mm? Endomag makes a 9mm insert for use in a standard 5.56/.223 pmag.
 

Mountain

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Hey y’all I’m wondering if anyone has looked into converting a fixed 10 round pmag to shoot from a 9mm upper? Also been a member for a little while this is my first post. Thanks in advance y’all!
Are you looking to convert an existing fixed mag lower?

Or looking to use a standard lower and build it as a 9mm? Endomag makes a 9mm insert for use in a standard 5.56/.223 pmag.

Despite the ability to make a fixed mag 9mm, I don't think anyone makes a speed loader for 9mm. There's at least two different sources for 5.56/300 BLK loaders. Something to consider.
 
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Are you looking to convert an existing fixed mag lower?

Or looking to use a standard lower and build it as a 9mm? Endomag makes a 9mm insert for use in a standard 5.56/.223 pmag.

I already have the lower just seeing how many different cartridges I can get it to shoot using one lower. And I definitely see the point of no one makes a speed loader. I had not thought of that.
 

Mountain

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Now here's a thought...

A 10 round mag for .458 SOCOM looks like this-
aprh100937-elander-458socom-10rd-blk-2.jpg
It's basically a 30-round 5.56 mag but will only hold 10 in .458.
No speed loader for that either but 10 rounds is a lot of lead. I'd suggest the correct 458 socom follower which won't hold 5.56. You need to swap barrel+gas block and tube as well as the bolt. Everything else can be same including BCG and buffer tube. Easier to just swap dedicated upper of course, and not mandatory but recommended to have an enlarged port.
 
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Now here's a thought...

A 10 round mag for .458 SOCOM looks like this-
aprh100937-elander-458socom-10rd-blk-2.jpg
It's basically a 30-round 5.56 mag but will only hold 10 in .458.
No speed loader for that either but 10 rounds is a lot of lead. I'd suggest the correct 458 socom follower which won't hold 5.56. You need to swap barrel+gas block and tube as well as the bolt. Everything else can be same including BCG and buffer tube. Easier to just swap dedicated upper of course, and not mandatory but recommended to have an enlarged port.

So feasibly I could take out the internals from a 458 socom magazine trim in the spring put that inside of my fixed mag 10 round pmag and probably have a four round socom mag? As far as reload time goes not concerned it would be for range use. (Until I move out of state) Definitely food for thought.
 

Mountain

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So feasibly I could take out the internals from a 458 socom magazine trim in the spring put that inside of my fixed mag 10 round pmag and probably have a four round socom mag? As far as reload time goes not concerned it would be for range use. (Until I move out of state) Definitely food for thought.

Actually you can probably get 3 or 4 rounds in the standard 10 round mag. You don't actually need a .458 follower and I don't use them in my pre-ban mags. The reason I recommend a follower is to steer clear of potential legal hassles. The .458 follower centers the ammo and if you try to load 5.56 or 300 blk with that type of follower the rounds will be spit right out of the magazine. The centering follower can make a post ban 30-round mag only hold 10 rounds of .458. You could use a 30-round 5.56 mag converted to .458 only for making a 10 round fixed mag .458. Hope that explains it.
 

amm5061

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Sooooo want to build a .458

I've got one. It's too goddamn expensive to shoot often and ammo is tough to find.

I still love it, though. Kicks like a mule with a 16" barrel. A shorty would be tough to handle, especially in pistol form without a good stock to soak up the recoil.

Actually you can probably get 3 or 4 rounds in the standard 10 round mag. You don't actually need a .458 follower and I don't use them in my pre-ban mags. The reason I recommend a follower is to steer clear of potential legal hassles. The .458 follower centers the ammo and if you try to load 5.56 or 300 blk with that type of follower the rounds will be spit right out of the magazine. The centering follower can make a post ban 30-round mag only hold 10 rounds of .458. You could use a 30-round 5.56 mag converted to .458 only for making a 10 round fixed mag .458. Hope that explains it.

I can fit 4 rounds of .458 SOCOM in my MidwayUSA Stoner-brand 10-rounders without a dedicated follower.

Lancer mags and USGI are best if you want dedicated 10-round mags for big-bore calibers from what I've found. Tromix and Wilson Combat both sell dedicated ban-state modified Lancer mags if you want to be super lazy about it.
 

amm5061

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So feasibly I could take out the internals from a 458 socom magazine trim in the spring put that inside of my fixed mag 10 round pmag and probably have a four round socom mag? As far as reload time goes not concerned it would be for range use. (Until I move out of state) Definitely food for thought.

The answer is no. Pmags suck ass for big bore rounds and require a lot of modification to work right. Your best option is to replace the pmag completely. 10-round Lancer mags are much better for this, or the USGI-like ones. Pmags have this weird tab in the middle of them that causes rounds to not push in or get jammed up inside the mag body.
 

Mountain

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I've got one. It's too goddamn expensive to shoot often and ammo is tough to find.

I still love it, though. Kicks like a mule with a 16" barrel. A shorty would be tough to handle, especially in pistol form without a good stock to soak up the recoil.



I can fit 4 rounds of .458 SOCOM in my MidwayUSA Stoner-brand 10-rounders without a dedicated follower.

Lancer mags and USGI are best if you want dedicated 10-round mags for big-bore calibers from what I've found. Tromix and Wilson Combat both sell dedicated ban-state modified Lancer mags if you want to be super lazy about it.

I used a Lancer mag for my .300 BLK fixed mag pistol. Good stuff.

Regarding the .458 SOCOM, once you buy the brass it's actually relatively cheap to reload. I'm running Starline brass and after many cycles of reloading I don't see any evidence of failure. Only had to trim it once. You definitely have to size it when new. Mostly I shoot Hornady #4500 300 grain JHP's which can be found for $19 - $20 per box. They don't look like they will feed well but at least in mine they are 100% reliable. Pushing them with 4198 powder. Fantastic accuracy to 100 yards and they dump a ridiculous amount of energy into whatever they hit.
 

wmass

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D&H makes a mag specifically stamped 458 socom and has their “big bore” follower that centers the round. I have their 50 beowulf mag It’s a standard 30rd AR mag body that holds 10 big boy rounds.
 

amm5061

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I used a Lancer mag for my .300 BLK fixed mag pistol. Good stuff.

Regarding the .458 SOCOM, once you buy the brass it's actually relatively cheap to reload. I'm running Starline brass and after many cycles of reloading I don't see any evidence of failure. Only had to trim it once. You definitely have to size it when new. Mostly I shoot Hornady #4500 300 grain JHP's which can be found for $19 - $20 per box. They don't look like they will feed well but at least in mine they are 100% reliable. Pushing them with 4198 powder. Fantastic accuracy to 100 yards and they dump a ridiculous amount of energy into whatever they hit.

Yeah, I've been saving all my brass so far, but I haven't had a chance to set up a reloading station yet. It's on the list of things I need to do.
 

Mountain

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Yeah, I've been saving all my brass so far, but I haven't had a chance to set up a reloading station yet. It's on the list of things I need to do.

Doesn't need any bells and whistles, but be sure to get a stout press. These bottleneck cases take some effort the first time you size them. Also I highly recommend Imperial Sizing Wax for a lube. I think the performance of this lube is one of the reasons I'm getting good brass life.
 
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I went with a JC Arms lower and a Bear Bear Creek 7.5", side charging upper. I have been waiting for a few finishing parts for a Aero Precision upper with a 10.5" Bear Creek barrel and hope to take both to the range next week to see how it runs.
 

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