Anyone here with a 9MM AR15? I'm thinking of building one.

[M1A4ME]

I know, it's going to be darned expensive to get what I want, the way I want it.

I don't want one of those leaning magazine Glock things.  I want a lower/bolt that use the Colt style magazines.

My idea is to build a 9MM pistol.

I want one that locks the bolt back when the magazine is empty.

I want about a 10" barrel (reason for that is I want to eventually buy/permanently mount a suppressor that puts the overall barrel length over 16", so I can put a butt stock on it and be legal - yeah, it'll be a pistol with a pistol buffer tube till then).

I want a free float tube, for back up sights and a red dot optic.

Anyone else have one/build one?  Good and bad on them?

Thanks.  Oh, this won't be a quick one.  Between the cost and the suppressor/paperwork/approval it will be awhile before it's done (stage 1 = pistol, stage 2 = suppressed carbine.)

Oh, why the AR15 9MM carbine?  To keep parts and manual of arms like the AR15's we currently shoot more than anything else.  Why the Colt magazine version vs. the Glock?  I don't own a Glock 9 (.357 SIG/.40 S&W, yes), have no magazines for them and the full sized Glock 9mm magazines are about the same cost (or more) than the full sized Colt style 9MM magazines.

[2morechains]

I built one back in 2016.  Started out as a pistol with 7.5? bbl, pistol buffer tube and a Sig Brace, then when PCC became a division in USPSA I converted it to a rifle with a real butt stock and 16? bbl and added a longer FF handguard. 

I built mine on a dedicated 9mm lower using a Quarter Circle 10 (QC-10) lower that accepts Colt SMG mags.  The lower is not cheap, but then again a quality conversion block for a regular AR-15 are not cheap either.  Since then a number of other manufacturers have come out with dedicated 9mm lowers (NFA, PSA, Nordic, etc.). The only 9mm specific parts on a AR9 are the barrel, bolt, maybe the buffer, and either the dedicated lower or a conversion block.  All the other parts are AR15 compatible (handguard, upper, buffer tube, trigger, etc).  The QC-10 has last round bolt hold open (LRBHO). 

I put a 13? freefloat handguard on it, Magpul K2 grip (prefer the more verticle), and a 6MOA C-More red dot and I was off and running with it.  As things progressed, made a few competition specific changes:  Added a second red dot sight on a 45 deg mount for the hard left leans, and upgraded my barrel to a Taccom ULW (5.5? barrel with an aluminum sleeve to make it 16.1?) to drop some weight and speed up transitions.  been very happy with the Taccom barrel. 

Pros:  AR9s are fun to shoot, cheaper ammo than .223, and USPSA has a division for them which has garnered quite a bit of interest within the competition circles. Did I mention fun?  32-round Metalform mags can be had for $20, and I added a +10 extension from TaylorFreelance for a total of 42 rounds.  No reloading on the clock for me unless the stage requires it. 

Cons:  Most AR9s are blowback design with a one piece heavy bolt.  The recoil impulse is actually a little more than .223 and can cause the dot to bounce on firing more than I like.  Unlike an AR15 with the two piece BCG, the AR9 uses a one piece bolt that is neccessarily heavy to keep the bolt in place long enough for the pressure to drop after ignition before it starts coming back (blowback design).  Along those lines, the buffer needs to be a little heavier than a .223 carbine buffer tho some people get by with a standard carbine buffer.  In the last year or so there?s been a lot of experimentation and innovation to come up with the ultimate buffer/bolt/spring combination that results in minimal recoil and ?dot bounce? for staying on target during rapid shooting.  I?m not entirely certain there?s the right answer for every application as it depends on a number of variables (ammo, weight of gun, shooter skill, what kind of shooting you?re doing...).  That said, I started out with a heavy CMMG bolt and 8 oz Spikes buffer and Tubbs Flatwire buffer spring.  That lasted about 6 months then my bolt went TU so I switched to the JP bolt and SCS buffer system and called it good.  Taccom, Blitzkrieg, MBX all have their pet buffer systems, and it would take a heads up comparison to figure out which one you like.  So good news, a lot of options if you?re trying to tone down the recoil/dot bounce, bad news is you literally need to try it for yourself. 

[fatboy]

Built a plain jane with Spikes lower, mag adapter and fixed entry stock. Plastic magpul BUIS, magpul 2 point, extended mag and bolt release, topped with a sparc ar 1/3 CW (home defense, not a long rang tac driver). Use the metal colt mags, the plastic ones are not real smooth going in or out. I hear modified UZI mags work as well.

Handy for a 100lb wife if I need some Shockwave backup (we all use a handgun in the house for protection while getting our rifles, right?).

Runs like a Singer sewing machine and very light recoil.

"Plain Jane" != "cheap" except to feed.

We all have some flavor of the SMG.

Have fun with your build!

[M1A4ME]

John A., did you build/make the silencer or buy it?

I thought about a magazine block and a standard AR15 lower receiver but after looking at prices (and thinking about just being able to look at it and know it's the 9 and not one of the AR's) I'm thinking about a dedicated 9MM lower.  I almost bought a Spikes Tactical lower yesterday.

Right now, the 9MM parts and the AR15 parts are priced so differently (9MM lower about 3 to 4 times more than an AR15/.223 lower, 9MM bolt 2X, or more, what a .223 bolt costs) that I realize it'll be a slower build.

The comments about low recoil are interesting as some people report higher recoil.  Lower recoil is one of the reasons for this new build.  Stage 1 would just be the 9MM AR pistol, so no big deal.  Stage 2, if I get that far, would involve the tax stamp, a trust so my wife would be legal using it, too, and the cost of the silencer and the permanent attachment to the barrel so I could put the carbine butt stock on it.

Just have to get the right parts since some parts seem to be made for use with Glock magazines, some for use with the Colt style magazines and some are supposed to work with either.

The "build" will be fun, they always are. 

[M1A4ME]

Thanks John A. 

I'm not sure I'm up to building something like that.  It might require some tools I wouldn't use very often.

Another question popped into my head?

Standard AR15 upper receiver?  Slick side (no bolt assist) upper receiver?  Or one of the dedicated 9MM upper receivers?

I'm leaning towards a "slick slide" upper if I can find one at a decent price.  But I'm not sure what/why others have used.

[swede69]

I used a quarter circle 10 lower colt style with jp bolt and buffer and a nice side charging upper by Gibbz Arms. They all make s top shelf products. And it runs great but get yourself a mag loader  from maglula because  your thumbs will get destroyed on the first day.

[M1A4ME]

I never felt the need for a magazine loader till I got the Browning BDM 9MM and the ParaOrdnance P14.  Then I bought a mag lula and it worked so well I got a few more for the sons/nephew and for me to carry one in the range bag and one in the target bag.  Ain't they great! 

[M1A4ME]

Well, Spikes Tactical 9MM lower (for Colt style magazines) ordered.  I'll pick it up when my FFl calls to let me know it has arrived.

Also ordered some lower parts and three magazines.

I have just had a thought (triggered by a 9mm/147 grain request for load recommendations I saw on another forum) about powders/bullets and a blowback action like this AR 9MM will have.  I think maybe I'll start a different thread for that as it's a reloading/ammo question/philosophy/experience thing.

[M1A4ME]

Oh, one other thing/question.

Magazines.  Any problems with any particular brand.

I missed the opportunity to by some metalform magazines on sale at CDNN.

I ended up ordering three ASC 32 round magazines as a start.  I've heard they were okay (didn't do a lot of research, just heard that).

I've also heard the CProducts 32 round magazines are hit or miss.  Work fine for some people, not so much for others.

Not sure how many other makers of Colt style 9MM magazines are out there or how they perform.

Any experience here, with the different brands?

[2morechains]

I use the Metalform mags.  Last ones I bought were from PSA when they were on sale for $20.  They?ve not given me any problems. 

[Atomic Punk]

I have the SB Tactical PDW brace on my Nordic Components 22LR AR pistol and love it.

https://www.sb-tactical.com/product/sbpdw/

Unless ATF changes their mind (again), I won't be going the SBR route.

[bang bang]

i got an OAK9.

But for your requirements you will be limited to the Colt system.

good luck on your build.  I say buy once cry once. 

but they are a hoot to shoot.

[M1A4ME]

Got some stuff in today (Spikes lower, KAK shockwave and tube, lower parts kit, hammer and trigger, magpul pistol grip with oil bottle insert, magpul back up sights, three ASC 32 round magazines, etc.).

Put the lower together, mostly, but not completely.  Left the carbine buffer spring and two potential buffers in the garage.  Oh, and the dual sling attachment piece that goes on the buffer tube.  I think I ordered a castle nut, but it didn't come it today.  I need to go back and look the orders over to make sure.

Oh, if you order a Spikes 9MM lower it has a bunch of the small parts already installed.  Not just the bolt catch and bolt release that are easy to see in the pictures on the internet, but also the front/rear takedown pins, springs, detents for them, the mag release/parts.  So the only parts I used from the lower parts kit was the safety spring/detent and safety, and the buffer retaining pin/spring.  The trigger pins came with the hammer and trigger I ordered (BCM nickel/Teflon coated) came with the pins.

Still, sort of, looks cool with a magazine sticking out of it.

Took pictures, I'll get them in here tomorrow when I have more time to organize stuff and pick out the most in focus pictures of the bunch.

[M1A4ME]

Receiver, Spikes Tactical 9MM, Colt magazine style.  Comes with everything but the trigger/hammer/springs/pins, safety/detent/spring, buffer retaining detent and spring.



The ejector looks to be held in by a screw.  So it should be easy to change if I ever need to do so.



The rear takedown pin detent and spring also seem to be held in by another screw.



I did a magazine (ASC 32 round) insertion and drop test with all 3 magazines.  They were all easy to insert/lock in and drop free.



Ambidextrous safety.  The 45 degree model.  Works fine now.  Need to remember to loctite the screw once I'm done with putting the rest of the parts on and before the first range trip.



The Armaspec lower parts kit (minus a trigger/hammer assembly).



The BCM trigger kit.  The trigger isn't light, but it's very "smooth."  I still haven't checked the pull weight yet.



Did you ever hear the "rule" that any tool dropped to the floor when working on a car rolls to the center of the car?  I dropped the sear while removing the trigger pin and it went (almost) to the center of the kitchen table.  I had to laugh as I was stretching to reach it.  Oh, pay no attention to the cat toy, they're like kids, they play till something else catches their attention and then leave the toys where they dropped them.



Everything installed.



Safety in the FIRE position.



KAK brace and tube (the tube has little identions in it to allow the set screw to lock it in place.  Got one of those "grippy" Magpul pistol grips and the oiler bottle insert.



My little oiler bottle made from one of those printer ink refill kits.  That long stainless steel tube makes it easy to get back into hard to reach/tight places and leave a drip of Mobil 1.

[Hemiscorpius lepturus]

The rear takedown pin spring setscrew is extremely convenient, moreso if you swap extension tubes with uppers to go between rifle/pistol combination, makes the job several times faster.

It should be a #4-40 x 1/8" size, and you need to trim the spring a bit or it wont compress enough for the detent to clear the pin. The spring is trimmed to just stick out maybe 1mm, then the setscrew is installed flush.

That was the setscew I was waiting for on my build, installed it last night, i used a 316 stainless setscrew from boltdepot.com