Discuss 9mm AR carbine as a go to

[Jpoe88]

Not sure how his cast stuff runs, but the fmjs run fine no stopages. Really torn on how I want to build this. I'd like to do a 16" light profile with a slim 7" tube, and a FSB or a flip up "gas block" and buis and maybe a 3x optic, and plain 6 position.

The whole idea is Light weight and streamlined. id like to not notice it's even on my back. Could consider a side folding adapter as well. Man, that would be sweet on a 10" setup too. Maybe I'll look into sbr this receiver.

[Dannybot]

I believe he's at like .06 using factory fmj, but .02 for cast

I don't see how that's really possible. the cheapest primers I have come across are 2.5 cents, then another penny for the powder. I guess if he's melting and casting lead... I'm about 9-11 cents per round.

On the 9mm AR: I have a Rock River mag block that takes Colt SMG magazines. I put together a conversion for my SBR that ran $600 (including mags) plus the lower, optic and the silencer I sometime run. This set up has proven 100% reliable, but not without issues. Getting the magazines in the mag well is not as ergonomic as a .223 AR or an M&P 15-22.

The mag well is very tight and without much funneling with that block in it. The feed lips push up against the extractor, so seating the magazine requires a very firm slam into place, but at the same time it is difficult to to force the mag in with much momentum because of the clearance of the magazine and the well. I am still working on this. I have started experimenting with radiusing all the sharp edges on the magazines, as well as very slightly trimming the left rear shoulder of the magazine where it makes contact with the ejector.

As for the build; I started with my SBR build that I have had for a few years. 4.5 # POF drop in single stage trigger, 5.5 oz 9mm buffer, standard carbine spring, and JP 9mm bolt, 11" Ballistic Advantage barrel with 1/2x28 threaded muzzle. This combination with some handloads that my pistol did not care for (too soft-- about 120 power factor in pistol) shoots soft, accurate and reliable. My wife and a friend have both used it in a USPSA match, I have used it in a falling steel match. So about 500 rounds in competition and about 800 rounds in testing and practice without a failure aside from the magazine falling out twice during matches due to not being properly seated.

So as to the original question: yes these can be practical AND reliable. With the right ammo, it could make a decent truck or defense gun. The Rock river block has worked from the very start for me. The Hahn has good reviews as well. I would make sure to get one that locks the bolt open. As for economy, parts are fairly available and reasonably priced. The Glock mag types require special, expensive uppers to lock the bolt open (but I think PSA is now making a lower with LRBHO in it).

If you are not going to use a lower you already own, then I would seriously consider buying a 9mm lower--they cost about the same as a good mag block. For the Colt pattern rifles, Metalform has the best reputation for reliability and can be had very cheaply. If you are starting with a new build and getting a 9mm lower, it is a toss up as to which is better; Glock or Colt pattern. I have shot a couple Glock pattern rifles and reloads may be a little easier, but they insert at a funny angle...

[Jpoe88]

The .02/rd is using the bullet he cast himself. He goes fishing for brass a few times a month and has a 5 gallon bucket full of 9mm range brass. He has bought primers and powder used and has also tracked his cost. It's a game to him. We are both looking at PCC for the simple fact of it being more fun and nearly as economical as .22lr

[RIGPIG]

$.02/rd doesn't even cover the cost of primers in most cases. I've been finding good deals on CCI 500 primers at $30/1000, which would be $.03/rd. I use TiteGroup in a light charge of 3.6gr, yielding 1,945 loads per pound, there's another $.01. I know there are cheaper powders out there. I got into a group buy on FMJs a couple years ago at $75/1000. Most ranges don't let you police others' brass, and charge $30-40 for a bucket of mixed brass. I'm in to my mouse fart 9mm loads at $.12/rd. I'd love to see a cost breakdown on your buddy's load so I can shave a little dough off my own loads.

[bfoosh006]

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[HMM]

Yeah those reload costs don't add up at all. I've got tons of free 9mm brass but my primer cost alone puts me in the 2-3 cent range. And I buy 10k at a time to get the cheapest price.

[Jellybean]

Coming from someone who wants a 9mm carbine or 9mm AR pistol for a "truck gun/range toy" I don't see the advantages over a .223.
I see the initial build cost advantage going to the standard AR pattern in .223 for me. (mags and plenty of spare parts around here somewhere)
Ballistically and lethality gives a strong edge to .223.
Ammo cost at $.20 per 9mm and $.30 per .223 is $100 per thousand rounds. Personally 1000 rounds a year through this setup is something I probably won't do regularly so the savings becomes a moot point.

What he said.
Pretty much right there why I ditched my plans for a 9MM pistol built, and went with 5.56.
I already have ammo and mags, spare parts, and frankly if I'm going to anything aside a handgun there needs to be some better ballistic advantages. Not to mention, I had planned for a Glock-dedicated lower, and a couple other "special" features that, once added up, put it to close in price to a 5.56 pistol build to matter on the budget side of things.

Now..... if NFA wasn't a thing and I could have a no-shit suppressed subgun, it may be a different story...

[wct097]

A little late to the party, but I'll throw in my $0.02.

To the OP, I'm not sure what "go-to" means to you, but for me, my "go-to" guns are those that I'm most likely to pick up to take to the range. In my case, I have a 16" .22 and an 4.5" 9mm and suppressor. I can't remember the last time I shot the .22. The 9mm is just much more enjoyable. It's cheaper to shoot than my 5.56 or 300BLK and I don't have to carry different ammo when I head to the range with my 9mm pistol. Clearly it won't perform like a 5.56, but mine has been reliable and always puts a smile on my face. No opinion on the "truck gun" aspect. I drive a Jeep and leaving a gun in it doesn't sit well with me, especially a suppressed SBR.

[ccoker]

I have a Wilson Combat AR9 pistol with an 8" barrel.
I bought it because I have been wanting a 9mm AR for some time and felt 100% confident that one from WC would run with or without a can.
It is a LOT of fun on the range, zeroed at 25 yards making hits on 8" steel at 100 is no effort.
I am running the 135g Hornady Critical Duty ammo with it and have killed several hogs at 30 yards or so.
Tested it at night with cans and with the WC flashhider that came with it, zero muzzle flash with a can and almost none with the WC flash hider

It has been 100% reliable and sits beside my bed at night.
It's a lot less noise/concussion than my 14.5" 556 and given the terminal performance I have seen on hogs I feel very confident in it at close range.
It fits nice in the door panel of my truck and I used it for an out of town trip last weekend with the family.

[AlphaTango23]

I just ordered a AR9 build for $800, but I went with nice stuff. I could have gone WAY more budget for probably $550-600.

PSA Glock lowers are around $120. Then you can get any LPK for $50 or so.

AR9s can be cheaply built, not as cheap as a 5.56, but close, all you need is a AR9 lower, 9mm barrel, 9mm comp, and a 9mm BCG. You can use AR15 parts for everything else.