AR pistol with fixed Mag? (In mass )

djbradles

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If it was 4473'd as "Other" then you're g2g, but honestly I wouldn't waste a good pre-Healey ban lower on fixed mag. Save it and get yourself a virgin new production lower.
That is if the virgin new production was a fair price. Here in Ma is there anyway to get one cheaper than $275? Unless you’re building it there is indeed a increased cost on the build.
 

amm5061

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That is if the virgin new production was a fair price. Here in Ma is there anyway to get one cheaper than $275? Unless you’re building it there is indeed a increased cost on the build.
If you find the right FFL to inbound it for you.

You could also just pick up an 80% for $40-60. More fun and you get the satisfaction of having really built it yourself.
 

Mountain

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You guys must have missed out on some of the group buys a few years back. I can't remember what I actually paid for stripped lowers but seems like it was ~$60, give or take.

I may check and see if I have an 'other' which I think was the way to do it in most cases. Assuming I have one, no biggie if I use it for this purpose. If I move to a free state, I still want an AR pistol and at that point can machine out what made the mag permanently affixed.

On another note, out of curiosity I contacted Mean Arms regarding their fixed mag loading device and 300 BLK. They confirm that although it was not designed for that, it will work just fine. Quick response and nice folks.
 

djbradles

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Just to be clear what is the minimum and maximun OAL rules of these pistols? Is it no less than x and no more than y? I know that for attaching a Vfg it needs to be >26”. If no foregrip or fingerstop does the OAL have to be more than some number?
 

amm5061

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Just to be clear what is the minimum and maximun OAL rules of these pistols? Is it no less than x and no more than y? I know that for attaching a Vfg it needs to be >26”. If no foregrip or fingerstop does the OAL have to be more than some number?

No OAL requirements that I'm aware of. The > 26" thing is only an issue if you want to put a vertical foregrip on. Doing so with an OAL < 26" makes it an AOW and you need a stamp.

Stick a finger stop or angled foregrip on it if you want. Those do not constitute a VFG per the ATF.
 

djbradles

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Is a carbine length buffer tube appropriate for an AR9 build? How about the buffer weight? Should I stick with the Dpms spring and buffer that I’ve already used with much success in my 5.56 build?
 

amm5061

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Is a carbine length buffer tube appropriate for an AR9 build? How about the buffer weight? Should I stick with the Dpms spring and buffer that I’ve already used with much success in my 5.56 build?
Carbine buffer tube is fine, but I think you're going to want a heavier buffer or a buffer spacer. I can't quite remember what you're supposed to do with 9mm, but it's one or both of those.
 

amm5061

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Can’t remember myself but someone here told me a stack of quarters would do, say $1.25?
Buffer spacer then?

Actually thinking about how the direct blowback system in a 9mm AR works, I would want both a heavier buffer and a spacer to absorb the recoil and prevent it from bashing out the end of the tube.
 

Dennis in MA

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Bear Creek has a 300BLK 10.5" upper for $185 or so. Good deal? Bad deal? Anyone have experience with their stuff? Just seems less than half of anything I see listed on Brownell's.
 

amm5061

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Bear Creek has a 300BLK 10.5" upper for $185 or so. Good deal? Bad deal? Anyone have experience with their stuff? Just seems less than half of anything I see listed on Brownell's.
I haven't heard anything good about them other than being cheap, tbh. That's pretty cheap though, so you could easily toss it if it's garbage.
 

DosesR1

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8A090DA0-403A-4021-A4E6-573515A7D2E7.jpeg
Finished this a few days ago go to range today first time loading it with the mean loader and bam jam ... got the hang of it them after and then this.... how...just how in the world other than that great little thing to shoot! No regrets ...
Other than living in this state

2BD021AA-3B2F-423C-A959-565DB921AA71.jpeg
 

Mountain

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View attachment 295086
Finished this a few days ago go to range today first time loading it with the mean loader and bam jam ... got the hang of it them after and then this.... how...just how in the world other than that great little thing to shoot! No regrets ...
Other than living in this state

View attachment 295087

Looks really awesome!

Jams with a fixed mag are pretty horrendous. Best to add some sort of stout pick to your tool bag, as well as some sort of pin pusher for the take-down pins, unless you install one with a grip knob.
 

amm5061

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Looks really awesome!

Jams with a fixed mag are pretty horrendous. Best to add some sort of stout pick to your tool bag, as well as some sort of pin pusher for the take-down pins, unless you install one with a grip knob.
Need an extended rear takedown pin with the knob for sure. That's almost a requirement for one of these.

Otherwise nice job. If a double feed is the worst you got I would guess the last round out of the loader wasn't fully seated in the mag. That does happen if you don't get the loader seated in the chamber quite right.
 

amm5061

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So I did end up jumping on this bandwagon. Here's mine:




Though I was planning on going full stupid and building a .458 SOCOM, Radical Firearms had a pretty good sale on a 10.5" 300 BLK upper- only $125. Besides the upper and arm brace, I could have built the entire thing from the parts pile. Had to have a Cookie Cutter comp because they are LOUD, and I added the Law Tactical folding adapter just because.

The Mean Arms loader works great with 300 BLK, which is a good thing as the fixed mag is a real PITA. This particular pistol runs perfect on supersonic ammo, doesn't like heavy subsonic. Might be the added interference of the folding adapter, or maybe I just need an adjustable gas block. No need for me to ever run subsonic, so no need to bother with the gas block. If I see a deal, I still might buy a .458 barrel and bolt combo and convert it. I'm already reloading .458 SOCOM so that's still not an expensive proposition.

Silly, impractical project but it's a ton of fun to shoot.

Very nice. If you're going to do the .458 thing, I probably don't need to tell you that you're gonna wanna change out that pmag for a Lancer. The cheap metal AR-Stoner mags from MidwayUSA actually work pretty good for .458 as well.

I wanna do a .458 shorty to join it's big straight-pull brother, but I would put that on my SBR lower. I can't imagine trying to control that beast with just a pistol brace.
 

amm5061

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IANAL, but if the metric was "a semiautomatic rifle that has an ability to accept a detachable magazine and has at least 2 of---", but the magazine is fixed, then the evil features are moot?

This is correct. A fixed magazine makes all evil features issues moot. Put as many on as you want.
 

Mountain

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Very nice. If you're going to do the .458 thing, I probably don't need to tell you that you're gonna wanna change out that pmag for a Lancer. The cheap metal AR-Stoner mags from MidwayUSA actually work pretty good for .458 as well.

I wanna do a .458 shorty to join it's big straight-pull brother, but I would put that on my SBR lower. I can't imagine trying to control that beast with just a pistol brace.
I have a 458 AR already. It packs a punch but is manageable. If I did go 458, yeah I’d have to cut out the fixed device and start over with the right mag. Takes what would be a 30 round 5.56 mag to hold ten .458’s. I’d install a centering follower so that it won’t hold 5.56 and potentially be a no-no.
 

jayhitek

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Need an extended rear takedown pin with the knob for sure. That's almost a requirement for one of these.

Otherwise nice job. If a double feed is the worst you got I would guess the last round out of the loader wasn't fully seated in the mag. That does happen if you don't get the loader seated in the chamber quite right.
Ha! It didn't even occur to me how a much a pain in the ass a jam would be if you couldn't drop the mag. Holy crap. what a nightmare. Even with the Extended take down pin, with the bolt partially back you can't open it up.. I can only imagine the headache.
Oof
 

amm5061

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Ha! It didn't even occur to me how a much a pain in the ass a jam would be if you couldn't drop the mag. Holy crap. what a nightmare. Even with the Extended take down pin, with the bolt partially back you can't open it up.. I can only imagine the headache.
Oof

The reason most of these designs use a pmag is so it's super easy to take the base plate off the mag and just drop everything out that way. I've had to do that once, the first time I used my loader and got a jam.
 
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