I have tons of ARs et al and now would like to build a 9mm SBR. The problem is I don't have any experience with 9mm on the AR platform.

I would like to build a short barreled rifle with a silencer that is recessed into the freefloat tube. Can you give me recommendations on:

1. What barrel to get and where (some place that will cut it down)
2. Any special requirements for the upper (flat top)
3. Bolt????
4. Buffer spring and buffer?
5. mag block and mags?


I look forward to any serious input you have. Thanks in advance.


Bomber

check out the pistol & rimfire caliber forum



there are tacked threads explaining the different styles.

The absolute best platform for an SBR 9mm has to be the Colt 9mm

Its by far the best functioning system and since they already sell a SBR barrel for them, its a no brainer.

I've seen people put mid or even rifle length ff tubes on a 7.5" 9mm barrel.  This covers a suppressor very well.  Looks pretty cool when its done too.

ADCO does a great job cutting barrels from what I've seen.  

As you know the 9's dont use the gas system so barrel length is not a factor when it comes to function.  A very heavy buffer will cure most short stroke and bolt bounce problems with the 9mm's.

I recommend the RRA 9mm buffer as It seems to work best with the colt setups.  Bolts for the 9mm are proprietary to the manufacturer of the barrel you go with, so thats not an issue either.  

YHM makes a sweet mag block that allows the use of unmodified UZI mags.  Its about 75 bucks IIRC and works very well.  As for magazines GOOD uzi's w/ out cracked feed lips and the colts are the best.

There is no special requirement for the upper unless you go with the oly/vulcan/asa style 9mm setup, then it would require a hole drilled in the upper to allow for the ejector.  The colt/rra style needs no receiver mod.  You however may decide to tap the gas port hole and thread a set screw in to keep gas and dirt from getting out, and in.

Should be a pretty sweet setup when its done!

Good luck,
Matt

Quoted: I have tons of ARs et al and now would like to build a 9mm SBR. The problem is I don't have any experience with 9mm on the AR platform. I would like to build a short barreled rifle with a silencer that is recessed into the freefloat tube. Can you give me recommendations on: 1. What barrel to get and where (some place that will cut it down) Click HERE, he is local VA,  click HERE for album, enjoy.... 2. Any special requirements for the upper (flat top) If you not picky, use what fits your needs.... I used a spare mystery funshow flat top I had laying around, the forward assist is decoration, along with the brass bump, or for mor money you can have a "9mm" upper with out the assist or the brass bump... the only purpose for the upper is to hold the barrel, and provide a runway for the bolt to travel. 3. Bolt???? You will either use the COLT style bolt from  COLT/RRA/ASA/Garrison  ir you doing a COLT pattern system.... Oly bolt and barrel is a different design,  so it is either COLT pattern,  or Oly...Oly also require the ejector to be mounted in the upper, so $$$ to oly, or $$ to machine shop to locate and bore the holes in the upper for the ejector. 4. Buffer spring and buffer? Do you want  CAR stock or rifle stock...  If CAR, run the CAR parts as intended for the short tube, and run with the 5.5oz "9mm" buffer to duplicate that of the std rifle buffer weight...  If you want more weight, there is buffers that run up to 8.5oz... If using rifle stock, run as is.. 5. mag block and mags? Variety of choices, they all serve same purpose, fill the 556 magwell so 9mm mag be held in correct position...   I went  Hy-Tech, use std Uzi mags, no fuss with setup, plug and play. The other blocks (colt design) will either give the option of bolt hold or not, top load  -vs- bottom load, and some other frills. I look forward to any serious input you have. Thanks in advance. Bomber

Great info thanks! I looked thru the gallery on the link above and coincidentally, I was at one of those machine gun shoots.


Bomber

I bought a RRA 9mm upper, complete, cheap.  Sent the barrel to Gemtech, who also made my suppresor, and they cut the barrel to my spec. Put the thing together [15min.] with an old Armalite tube and measured where to cut the tube. It comes off in a jiffy and I am tickled pink with it. Sights or Eotech is my last decision to make, now that it has proven to be 100%. Its on a Colt lower.

Well I made some progress. I'm getting a Tros 5.5" 3 lug barrel and a SWR Trident suppressor. I will start with a pistol length FF tube and move into a mid length Samspon FF tube. I would like to us Pro Tech mags but need advise on the mag block.

Bomber

W/O starting a new topic can someone tell me how to install the RRA 9mm port door kit and case deflector? I figured it out but I got this spring, Its like 5mm long, little bit bigger then a extractor spring.

BTW here is mine..
http://img.photobucket.com/albums/v506/RobertKM/9mm%20AR/9mmAR001.jpg

Waiting for a new front sight and FH.

think theres a hole in the deflector facing the upper in which the spring goes into. have seen part of the spring when cleaning my 9mm carbine.

Here's an update on my progress.

So far I have accumulated the following parts for my build:

1. Ameetec side charger upper - wanted something unique
2. Hahn - top loading dedicated mag block
3. 4 Colt 32 rnd mags and 6 Promags
4. RRA Buffer
5. RRA bolt
6. Troy Carbine length FF tube
7. Magpul 93b stock
8. Eotech 511 - shifting the compact version frm my AR and will replace with a 512
9. RRA hammer
10. Stag LPK


Here's what I have on order waiting delivery:

1. Rock River 9mm marked lower - expect in about a week
2. Tros 5.5" 3 lug barrel - expect in about a week
3. SWR Trident Suppressor - hopefully within a few weeks

I don't plan to have any BUIS. Does anyone know where to get a mag loader for the Colt magazines?


Bomber