9mm AR-15

[HIG541]

Anyone build one of these? since it is a pistol caliber round are you able to legally have a very short barrel with a telescoping stock? any help would be greatly appreciated (9mm lower suggestions?)

[NSR500]

A 9mm AR still needs to comply with Federal and State law in California.
I have one built with a CMMG upper/lower combo.

[John Browning]

Rifle is a rifle, same laws.

I am using a Hahn dedicated block in a CMMG lower and have been happy.

[Saber2Golf]

Anyone build one of these? since it is a pistol caliber round are you able to legally have a very short barrel with a telescoping stock? any help would be greatly appreciated (9mm lower suggestions?)

I own a RRA LAR-9, which is a dedicated upper and lower receiver, but the idea is the same.

A short barrel and a stock is a no-no in CA and needs a tax stamp in other states. However, a 9mm AR is a good candidate for an AR pistol build IMO (any barrel length, and a pistol receiver extension, no stock). However, this requires a mag lock and a 10rd mag, and that alone may take away some of the appeal.

As for a lower, there are adapter blocks, and there are dedicated lowers. They are functionally the same, and while the dedicated lower requires fewer parts, the "regular" lower can be used with different uppers. I'd probably pick an upper that I like in 9mm and then figure out the best/easiest way to run a 9mm lower.

Also note, the adapter block requires a mag lock, and the lower receiver may need its own mag lock as well. This complication isn't something I've had to figure out with my LAR-9 since there's no adapter necessary.

[shark92651]

Also note, the adapter block requires a mag lock, and the lower receiver may need its own mag lock as well. This complication isn't something I've had to figure out with my LAR-9 since there's no adapter necessary.

Actually the 9mm magwell block still works with a standard AR magazine catch so you only need a standard bullet button or raddlock in the lower receiver, there is no additional maglock required for the adapter.

[NorCalK9.com]

Get a just right 9mm carbine!

[CHS]

Get a just right 9mm carbine!

That's not a 9mm AR15. The OP was asking about 9mm AR15's, so why did you suggest this?

[CHS]

Yes, I've built one and it gets a lot of use.

9mm AR's are great. I've built a "Colt pattern" one from an RRA upper and a dedicated CMMG 9mm lower.

As far as the short barrel, it doesn't matter what the rifle is chambered in as a rifle is a rifle. If you build a 9mm AR15 with a short barrel and a stock you will be violating California AND Federal law.

What else do you want to know?

[tuna quesadilla]

That's not a 9mm AR15. The OP was asking about 9mm AR15's, so why did you suggest this?

NorCal K9 hates AR15s and anything related to AR15s.

(I'm only joking, but I think we all know what a big AK fan NorcalK9 is)

[Sicilian]

I did a review of an Olympic style 9mm a few months back - here

They are not compatible with the Colt style, but I think they have several advantages. There are dedicated magazines for them, which do not require a magblock. The mags are a little expensive. But, if you factor in the savings from not having to buy a magblock it evens out. You also save a little more by not having to buy a special buffer and hammer (or a ramped bolt). Sorry if I'm writing over your head, but these are things to consider with a 9mm AR.

[Old Flash]

Yes, I've built one and it gets a lot of use.

9mm AR's are great. I've built a "Colt pattern" one from an RRA upper and a dedicated CMMG 9mm lower.

As far as the short barrel, it doesn't matter what the rifle is chambered in as a rifle is a rifle. If you build a 9mm AR15 with a short barrel and a stock you will be violating California AND Federal law.

What else do you want to know?

CHS,
I also have a complete RRA 9mm upper assembly and a dedicated 9mm lower, and wondering if this is a plug and play set-up for you? What did you have to do (if any) to make your 9mm AR work? Thanks in advance.

(Sorry, I don't mean to thread jack.)

[CHS]

CHS,
I also have a complete RRA 9mm upper assembly and a dedicated 9mm lower, and wondering if this is a plug and play set-up for you? What did you have to do (if any) to make your 9mm AR work? Thanks in advance.

Mine was pretty much plug and play.

I use the C products magazines instead of RRA/Uzi magazines, so the bolt-stop works and I added the Spikes buffer spacer so I never have to worry about breaking the bolt stop.

With unramped bolts like the RRA's, it's a good idea to use the KNS anti-walk/anti-rotation pins. They are generally useless on standard AR's, but come in handy on the non-ramped 9mm's.

[Old Flash]

Mine was pretty much plug and play.

I use the C products magazines instead of RRA/Uzi magazines, so the bolt-stop works and I added the Spikes buffer spacer so I never have to worry about breaking the bolt stop.

With unramped bolts like the RRA's, it's a good idea to use the KNS anti-walk/anti-rotation pins. They are generally useless on standard AR's, but come in handy on the non-ramped 9mm's.

Great info! Getting the buffer spacer and using anti-rotation pins gives me a good starting point to start building up my lower assembly. Thanks.