Building SBR- Exploring 9mm Options

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?


Sent from my iPhone using Tapatalk

I will attempt to answer several of the questions.

1. I have a 16" Lone Wolf and a 9.5" QC10 9mm lowers, both dedicated Glocks
2. I have Glocks, so I appreciate dual use magazines, plus there are nearly 100x more Glock guns out there than dedicated Colt pattern magazine guns
3. Shooting today, I was reliably ringing steel with a 9mm pistol and long gun at 50 yds; I simply do not shoot 9mm past 100 yds, as you lofting the round out there with four inch plus hold at that distance IIRC... Expect humble accuracy, not 1 moa
4. 9mm is convenient as a pistol caliber at my home range, quieter than .223, significantly less blast than .223, has a similar recoil impulse to .223 and is marginally less expensive than .223

I have never seen a colt mag at a gun store, glock mags are a different story

Sent from my SM-G900P using Tapatalk

The Glock mag lowers bother me, I'd try to handle one before buying. The angle the mags are inserted is very odd feeling to me, being used to a regular 556 AR.

The PSA uppers Look to be standard Colt style, with a bolt that also works with the Glock mag style.

Quote:

---

Originally Posted by Todd.K

The Glock mag lowers bother me, I'd try to handle one before buying. The angle the mags are inserted is very odd feeling to me, being used to a regular 556 AR.

The PSA uppers Look to be standard Colt style, with a bolt that also works with the Glock mag style.

---

Interesting info, I've never thought that the mag insert would feel all that different. Mine is finally shipping to my dealer so I'll have to try that out once I get it built.

I was in the same boat: I wanted a shorty 9mm, but for shooting local steel matches. I went with the Hahn bottom load mag block because I have two SBRed lowers, and what I have researched, Hahn was the way to go for non dedicated set ups. I saw no reason to purchase another lower, especially a lower that was "stuck" in 9mm. Here is the build spec:
- Hahn bottom load
- Ballistic Advantage 5.5 barrel - they offer 1/2x28 threaded barrels for cans.
- Spinta Precision bolt
- Slash's Q-buffer/normal spring
- Aero upper

It shoots fine @25 yds. I see no reason to shoot 9mm past 50yds. The only hiccup is Tula ammo (underpowered, doesn't eject 100%), which is a bummer because that is some cheap shooting! Win White box and run of the mill Remington green box shoots fine.

I recently completed my 9mm SBR. For magazines, unless you are up to your EYEBALLS in Glock mags, get something in a Colt pattern. The mags themselves can be pricey, but they do support last round bolt hold open, don't require a specialized bolt, and if you ask me; they look a lot cooler because they aren't canted to the rear.

PSA lowers are cool, and they seem to be a direct copy of Black Creek Precision (on which my sbr is based.) they may talk about compatibility with uppers, but that mostly applies to side chargers, and other non-standard fare.

Effective range/accuracy? Like in combat? 100 yards if you know what you're doing. But, forget all that stuff for a minute. Not every gun has to be a killamajig worthy of Carlos Hathcock himself. These things are great fun and in a pinch work at all home defense distances, which you will almost certainly never use the gun for. 200 yard shooting with 9mm carbines is possible but not that thrilling IMO. Not sure what kind of accuracy you can wring out of them. Stick with rifle calbers for anything beyond 100 yds myself.

9mm conversion kits aren't my area so I will avoid that topic mostly, while I will say the name Hahn Precision gets a lot of use in that circle.

Companies of note in the 9mm game seem to be YHM, Ballistic Advantage, Colt, Odin Works, Model 1 Sales, Spinta Precision (even if the "cosmetic blem" bolt I got from them was pretty terrible and required hacking at with a dremel to make function,) and MAS Defense. Other than that, it's a lot of smaller garage machinist type places making the really neat stuff. Like SlashBuffers, TROS USA (BEWARE the ridiculous lead times,) Macon Armory, and there's more coming out all the time.

You mentioned 9mm being quieter. Are you going to run a silencer? If yes, you might consider an even shorter barrel. 8" is the max in my mind for performance. 3.5 is great if you want to keep most ammo subsonic. personally I went with 5.5 because it was about the minimum to avoid a handguard longer than your barrel, allowing me to shoot with or without the silencer