Been a long time since I even looked into the 9mm AR world.  IIRC the last time was when the bottom loading VM HyTec block had people's attention and C-products hadn't started producing mags yet.

So who's now the go-to for drop in blocks?  I'm thinking of dropping it into my SBR when the mood suits me and for doing some cheaper destructive testing of some homemade polymer lowers.

IDK, my VM is still rocking.

 
I was unhappy to find out that they went belly up and are no longer being made.  Would have been perfect for what I'm wanting to do.  I want something that's fairly reliable, but more importantly something that is easy to convert back and forth.  BHO is nice, but not necessary.

I don't know the manufacturer, but a buddy of mine has an insert that fits in to the mag well and secures with an Allen screw.

Once it is installed it's invisible and I think it takes UZI mags.

His receiver is registered and the 9mm upper runs flawlessly with that device in place.

I wish I had more info, OP.

AMM Arms

MAHA

That looks like it.

Thanks.

RRA is my go to...
I have built 4 for myself and others.

ALL are great runners ! !

Spikes are OK, as I used one and it ran well.

AVOID LIKE THE PLAGUE, AMERICAN SPIRIT ARMS.
Got it at Brownells. Brownells only sells the best, RIGHT ?

I almost didn't build another one, as the one I tried it on was a JAM A RAMA.
Put on a RRA and the rest is history.

9 m.m. is my favorite of my AR's

I have 9's as well as ...
 .22 LR  
7.62X39
 300 blk
   5.56    

They are like my children, man .

This is the correct choice.  Mine has run flawlessly.  

AMM Arms works flawless.

About that whole pesky out of stock thing though.....

I'll give them a call after work and see what they ETA is on the next batch.

Palmetto has been teasing us with a glock compatible block in the near future. I'm holding out hope..

Fruity lowers?  

IIRC, the Uzi mag adapter isn't being made anymore.  You can make one out of a standard Colt mag adapter & an Uzi lower flat or magwell.

the email I got said 12 to 14 weeks for them to come back in. they had an issue with the last batch making them unusable.

 
The fruitiest .

Hahn bottom loader is excellent, use Colt or Metalform magazines.

Hahn dedicated is great as well.

How good/bad are the pro-mag ones?  

Hahn are my 1st choice, but that price compared to the AAM one (when in stock), is a tough pill to swallow since this wont be going into a dedicated lower.  

OP - of course, once you get one - you can cast it.  

My promag block works good with metalform mags. I think you can cut the "ears" off the promag block and then you can swap it out without removing the bolt catch.

I'm assuming that is a top mount? Does the bolt catch need to be removed to install it? How does it compare to the Hahn dedicated block? Nevermind - googled the answers

I'll Answer any way.  The AMM Block is a bottom loading that locks in place the rubber stops.  My room Mate and I have one and we have had no issue with them.  The look very simular to the Spike block that was discontinued.  

MAHA

Hahn top loader.

anyone built one with the PSA 9mm pistol kit yet?
i have a personal interest in that specific kit.

Mine came from RRA with the upper.  The set screw pushes out one or two pins that hold the block firmly in place (it has been a while since I installed it). The set screw doesn't actually touch the lower.  It hasn't moved a fraction of an inch since I put it in.  I have 6 mags that regularly cycle through the gun, so it has had a lot of testing.  Modified Uzi mags work with it, but Metalform/Brownells mags have the bolt hold open feature, which is not underrated.    They seem to be more reliable than Uzi mags.

I have their rifle kit being delivered next week, with one of their stripped lowers for a customer. I will give you an update after it's put together and tested.  

AWESOME!!

This is what I'm using, works great. No bolt hold open with the top load though.

I'm using RRA and works just fine.

I chased this rabbit all around after ordering several Anderson Lowers.  AHM said in their email it would be late October before the next batch came out. They will process the request folks have sent in once the materials are sourced and ready.
SO on the low end you get the PSA non adjustable unit, or go with the more expensive Hahn unit for $150 or so from Brownells. Well after ordering my Lowers, parts kit, MOE stock and Hahn Mag block.....I learn BlacK Creek Precision has a dedicated 9mm Lower on sale for $125.

All of  sudden the dedicated lower is starting to look more cost effective. And then /I decided to do the right thing and just get one of each. So after the Labor day sale, I expect to have  a complete upper and see which platform runs the smoothest. Maybe they will both run fine and ...then what?

Many step have been taken but the journey is far from being complete.

saw that too, and considered it, because the stuff I bought is burning a hole in my pocket trying to get it to run waiting for that mag block.

I am holding fast because apparently some mags may or may not work on dedicated lowers. since the mag block is adjustible, you can make up from some mag issues.
I already bought the mags so I am going to wait now for the "right" mag block to run them in.

I was asked by a poster here to demonstrate a procedure for installing a 9mm mag block on an AR-15 lower.

I had ordered at PSA 9mm rifle kit and a PSA lower.  They came in today.

Here is the assembled upper and the lower parts in a bag



Here is the Mag Block




Here is the unramped Bolt



SORRY PHOTOS FROM THIS POINT ON ARE SLIGHTLY OUT OF FOCUS

Here is the assembled lower prior to the insertion of the mag block.  BTW, the rear pivot pin
hole is now threaded for a 4/40 set screw ala Aero Precision making assembly much easier.
The lower was a PSA blem but I could not find any cosmetic issues.




Prior to attempting to insert the mag block I cover it with grease (using just standard brake grease)




I then place the mag block in the lower and lightly tap with a rubber mallet on the feed ramp to seat the block
Do not tap on the back of the block or you could damage the ejector or ears. Lightly tap it into place. You don't need
to beat it into place.





Check to make sure the block is even with the top of the lower


And that the cut out for the mag release is lined up with the mag release in the lower


Install the mag release and check to make sure the magazine is properly held in place and releases freely

Then install the upper and make sure it fits properly on the lower.  At this point in time I will load up 9 mm dummy rounds
into a magazine and test feeding from the mag to the chamber, along with extraction and ejection.  Next step is a trip to the range
to test actual firing.




There is not a significant time difference between assembling a 9mm lower over a 5.56 lower.

If you don't care for the smooth sided upper you can replace the upper with a standard 5.56 upper.

There are those who prefer a ramped bolt over a unramped bolt, since the kit came with a 9mm hammer, I didn't see
the need for a ramped bolt.

If you decide to SBR a lower, I like the idea of the top load mag block because it's easy to switch calibers. I can just take out the mag block, and switch the buffer and upper to 556/300.

LOOKS GOOD!!


**does it lock back on an empty mag?
I'm interested in the range report to find about how the PSA mags worked.. (I hear that they work well with their kits)


Mama's Birthday, Our Anniversary, and my youngest daughter's birthday are coming up, but after that.. I'll have one of these on my bench.

I purchased the PSA 9mm kit and 3 of their magazines. Using the PSA LPK and magwell block, I assembled this on a standard Anderson lower. There were no issues at all. The magwell block slide in easily, no need to hammer or add grease. I ran 200 rounds thru it this past weekend with no problems. The bolt held open after the last round, the magazines dropped free and the rifle is damn accurate (granted I was only on a 25 yard range) using a Vortex Spitfire RDS.



I also had the bolt ramped.



 

Function testing went well. 50 rounds of FMJ military ammo, 50 rounds of reloads consisting of RCBS 125 grain truncated cone slug over 5 grains of Unique.
No malfunctions, feeding, or ejection problems. The bolt does lock back  (I found the problem and corrected it, it was an improper install of the bolt catch on my part)

When I was policing up my brass I found the case shown below.





It appears to have fired when it was not fully chambered.  It may have been a function of a high primer or the case not seating completely.
I didn't notice anything unusual at the time, so I am not sure when it happened. In any case, it is a reloading error rather than a rifle error.

whoa..
that case is trippy lookin'

Ummm.  I don't think the blowback bolt has the same protections against an OOB as a locking AR bolt does.  You positive it's your brass?  Same headstamp?

OOB?
(out of battery?)

Think it's one of the possible explanations for that brass, no?

I was asking about the nomenclature, not questioning the conclusion.

I would think that if a bolt was out of battery during ignition, that it would be more likely to cause the bolt to blow backwards or dislodge the primer than re-shape the brass..

but I have absolutely NO IDEA.. I'm not a reloader, nor am I an engineer.

This is why I went with a separate magazine block.  Mine is a Rock River block that came with a factory 9mm Carbine, but I can switch it to my SBR lower and run a short barrel whenever I want.  

The PSA 9mm bolt's firing pin has a spring that keeps it from going forward except with a hammer strike, and the rear of the firing pin does have pretty close to the same protection you see on a standard (shrouded) AR carrier.  I think it's possible a non-standard round might have caused this problem.  Interested in hearing from the OP on whether or not that was definitely his brass...

Check the chamber, you either have a case broke off or your ammo is not fully seating in the chamber, your lucky no cases blew out, stop and figure out WTF before you shoot her again.  Reloads?   A high primer = no fire not early fire, high primers will Not go off most of the time.   They need to be flush or below the case head, this looks like ammo that will not drop in and out of chamber freely