ok  don't know jack about building an ar ,  I ordered a complete gun 3 weeks , ago company all of sudden sends me refund,  thye never answer calls . so I finally got someone and they said they thought at time they had one in
stock .  meanwhile  im buying some stuff to mount my suppressor on it .

I cant find any complete  ar 9  with fosteh trigger. I know gimmick or whatever.  

I want atleast 9 inch barrel  . with glock mags .  

so I thought maybe I should buy parts and just so it myself .  now if any experts out there

that can list things I need id appreciate  it , or  if got no time I get that also .

There’s plenty of good 9mm builders that you can order an upper or compete gun from. Then you can add the binary trigger yourself.

But if you want to build it yourself, you’ll need an upper receiver, barrel, 9mm bolt, 9mm buffer (with spacer if it’s not an extended style buffer), buffer spring, handguard, lower receiver, lower parts kit, buffer tube, stock (or pistol brace if barrel is under 16”), and tools to assemble everything.

Bolt and buffer weight is debatable. General rule is 21 to 23 ounces combined runs the best. Some say less is better, some say more is better. Some like standard carbine buffer springs while some like .308 springs.

You’ll want a ramped bolt that’s compatible with the style of mag you’ll be using. Some bolts aren’t compatible with certain uppers (like a Faxon bolt with a Spikes upper), so watch for that. The ramped bolt means you have more trigger options.

Lowers depend on a mags you want to use. You can get dedicated lowers, or use mag well blocks to adapt a normal AR15 lower.

Barrels are something to be cautious about to make sure you get a good one from the beginning. Traditionally, 9mm barrels don’t have feedramps or even feeding cones because the lowers (and lower adapters) that take Colt mags have feedramps. Non-Colt lowers relies on the mags and bullet shape to get the round into the chamber. That’s when the lack of barrel feedramps cause problems. The better barrels have rounded the sharp corners of the chamber opening to create some sort of feedramps. Taccom (and perhaps others I’m unaware of) have designed barrels with actual feedramps.

Keep in mind that I’m just an amateur when it comes to AR-9’s, so listen to the pro’s over my advice if there’s conflicting advice.

Everything you need to know about building your own, all in one place:

AR9 blowback basics and common problems/troubleshooting/fixes all in one post. "Lots of 9mm AR information"

I built 2.  The first was a disaster and resulted in the post I linked above to help others.  The second, using the lessons learned in that post, ran perfectly from the start.

Macon Armory barrels have Rudy's "guaranteed to feed" feed ramp machining, and it really works. Don't buy a cheap barrel (or bolt).  You'll likely regret it.

FYI - Binaries are finicky.  After over a year I took mine out and swapped for an AIM SSTAT.  Could never get it to run perfectly.  No hammer follow, but it had other issues.  Lots of troubleshooting/ammo used.

ke arms ambi lower
ar parts kit minus trigger
alg act trigger
buffer tube
carbine spring
qc10 buffer
qc10 bolt
upper
cmt rail
barrel cut for glock
muzzle device

I've got a QC 10 lower ...........Ive used three different uppers on it...........one had to be sent to Macon Armory for his magic...........other than that........Ive never had a failure to feed or eject...........runs great and is my shit hit the fan..............stick..................NFA barrel, Gorilla machining barrel, and a Faxon that sucked...............

Your issue will be a lower.  Either glock-mag only, or standard w/ an adapter block.  LPKs, etc are still around just receivers are hard to get.

I like my FM 8.5" side charging upper.  Runs fine on standard lower w/ Endo mags.  Came w/ Glock cut bolt.  Aim Surplus still has/gets them.

Alternatively as said build a upper.  Again, finding the actual upper receiver will be the sticky spot, I've seen plenty of 9mm barrel offerings from various groups while looking for a 762x39 barrel in the last week or so.

I'd get it working w/ a standard trigger first, then go for the fostech.

Topic Moved

Things you could do.....

Go to google....Type "9mm AR build thread ar15.com forum"

OR go to your local dealer and have them order a complete 9mm AR15 from a manufacturer that has one in stock.

OR go to the Equipment Exchange and find a complete gun for sale.