9mm AR SBR

[DenverDave]

I have wanted to build a PDW style SBR for a while now. Had intended on going with a 10.5" 5.56 barrel as 300 aac ammo is too expensive. Recently I have been reading up a little on dedicated pistol caliber AR Set-ups and am interested in exploring this option a little more.

I have primarily been looking at the PSA uppers and lowers. They offer two style in 9mm, Glock or Colt. Is there any advantages to one over the other? I don't own a Glock so don't have Glock mags around which I could see as a reason to go with a Glock style lower.

Also regarding the PSA offerings are the lowers compatible with other brands uppers or the other way around? The description does say it's designed to work PSA uppper/PSA Lower.

Apart from PSA, other companies I should look at?

Also, how about drop in 9mm conversion kits, do these generally work well? Any specific brand recommended?

The pistol caliber set up is attractive to me because of the price of ammo, able to effectively use shorter barrel, and quieter to shoot. I do have concerns about the effective range and accuracy. I know a rifle caliber will out perform a pistol cal, I would like to know by how wide of a margin.

What type of range / accuracy can one expect a 9mm SBR fired from a 8"-10" barrel? Obviously this is not a precision platform, and it depends on factors like barrel quality and ammo quality. But a ball park estimation of the platforms capabilities , for example is 2 MOA out to 200yrds possible?

[MarkCO]

If you are in Denver, check out MachineGunTours. They have several...Jard, SIG, their own on a QC10 lower.

Tuning an AR15 9mm baffles some, usually ends up damaging Bolt hold open, or they just skip it. Glock mags rule the roost. I have shot a few matches and everyone who wins uses Glock mags while the Colt mag guys are having jams and not as much fun.

2MOA at 50 yards is reasonable, at 200 no. While I have shot mine with tuned loads past 200, 100 yards and 4 to 5 inch groups is the reasonable effectiveness for a 9mm PCC.

[Jim Watson]

IDPA shows a PCC Division in 2017 draft rules. Minimum barrel length 10".
It does not comply with IDPA 1.2.1.1 or 1.2.1.2 in that it is not concealable or suitable for all day wear, but I doubt that will stop them from trying to get into a new market.

So you will likely have a place to shoot your imitation burp guns where score is kept.

[HiBC]

I will ask "What is the perceived advantage over the 5.56?"

Ammo cost? I'll leave that up to you.

Controllability? The 9 is blowback.That ups the effect of recoil.Heavy bolt,etc.I doubt your effectiveness on target(speed) will be much better with a 9mm.

Real life effect on a bad guy?? I'd think even from a SBR,the 5.56 would be better.

You do what makes you happy!! Just something to think about.

Cost per round,if you reload,a primer is a primer.(exception.Mil-spec primers run high.Maybe 1 cent a primer)If you find once fired 5.56,it can be had,unprocessed,for under $200 for a 5 gal bucket(approx. 3700)I agree,9mm brass is cheaper.

Powder,per lb,is about the same,but you use about 4,maybe 5 times as much per load in 5,56. So 4x cost to 5.56.

Both 55 gr and 62 gr FMJ bullets can be found for 10 cents to 13 cents for Hornady quality.

[Chainsaw.]

Im in the exact same boat, wanting to build a 9 sbr/pistol. Ive decided on Quarter circle 10. Nice stuff. They seem to have it squared away if yoibuse their upper/lower and bolt. Everthung else is just AR stuff.

To me a 9mm is very desirable, I reload so ammo is Cheap, stupid cheap. Almost no blast is nice vs a stubby 556.....ouch. Its a wonderful suppressor host in my eyes with subs. I have a goats boat load of glock mags so theres that.

I say go for it, especially if you already have a rifle.

[rjrivero]

Suppressed 9mm SBR's are too much fun.







Make me giggle every time I shoot them.







https://www.facebook.com/rjrivero/vi...73554920955315







This video isn't much to see, but you can hear what I mean....

[9x19]

When I built mine DDLES (whose design is now the QC10) was having alot of issues, so I went with Lone Wolf... Other than a bit more meat in the lower, I like it just fine.

For times at the range it is so much more fun that a short 5.56 or even the .300

If I had to use in inside the house, well, the blast would be alot less than either of the others as well.

Mine has a 10" barrel with linear comp... much shorter and I might as well use my Glock 34. (which is my primary home defense weapon)

Good luck.