Ar 9mm

[Squib Joe]

I did see an AR at Bill's that took 45 ACP ammo, and the end of the barrel liked pretty much like a Thompson. Dunno if it would take Thompson mags or not, but the magwell looked to be double stack dimensions. If the action's the same rotary bolt, that would mean that you could probably go 45 Super and with a 16"barrel and the right powder you might be able to come up with some pretty respectable loads.

I'd suggest a new barrel and diddling the mag lips to make a 50GI AR, but I ALREADY have a 50AE AR, so there's no point, and that one is supremely badass!!

Those are JRC Carbines -strictly speaking not an AR.. and they use Glock 21 (or KRISS) mags. They make another version that uses 1911 mags. It's an ambi carbine too which is nice

A pic from Oleg:

[Dave Timm]

I like the 9mm ARs for a variety of reasons. First is it does make a nice training platform as rounds are a little less expensive, this also can be very beneficial in shoot house type environments that only allow pistol calibers. Another aspect is in some situations a 9mm SBR can have some benefits as well over a 556 SBR, finicky ness being a big one. Some ARs when they get short have issues, dwell time, pressure, bark etc etc. since 9 is a pistol round it does pretty well here. Would I go pick one as my main patrol/defense rifle, no. Do they have their place, sure if you think you can benefit from one. Also, like my MP5 they are fine so why not .

[yonse]

As others have said, price and magazine comparability with pistols can be reasons but another could be recoil. The recoil of an AR-15 is no issue for most healthy adults, but for some others it can be. A pistol caliber AR-15 may be a viable option for people who have shoulder injuries or implanted medical devices that may prevent them from being able to shoot even a 5.56/223 rifle. I would imagine that they might also be slightly more controllable if you were to put a bump-fire stock on it as well.

[JustPlainT]

Only real argument I can make for a pistol caliber carbine that still has the full 16" barrel is noise. Since in MN, you cannot legally obtain a suppressor, you have to make do with whatever you can legally buy. A 9mm in a 16" barrel is a lot quieter than a 5.56/.223, from my own observations.

I could see the argument made that if you wanted to be able to use the gun for home defense and be able to hear things after shooting, the 9mm may be the better alternative.

[ARBuilder]

I like the pistol ammo running through the AR platform and my main reason is because you can. I have an AR pistol I have been building that shoots 45acp and when that gets completed I plan on starting one in 9mm running the DI system on it as well.