Home Forums Hunting & Shooting AR and Tactical Rifles AR "Pistols"....school me

I've been kicking around the idea of getting one for a truck gun. Probably 10 inch or so, probably .300 blackout with an eye toward a suppressor down the road. I'd like to hear a little from those who've BTDT. Any preferred makes, features?

Been told by several who built 300 BO pistols go with a 7.5 inch barrel, if you plan on running a suppressor. PSA makes a good upper Karri’s guns makes a great upper. I have a 10.5 Karri’s upper in a 5.56 and it’s a great upper so far.

I have one in 5.56 and 6.5 Grendel. 10.5 and 12.5” respectively. The SBA3 brace changed the AR pistol world. I haven’t shot the Grendel unsuppressed but it has been a great deer gun for the kids and me this fall. The 5.56 is blasty (bad concussion) unsuppressed but not terrible. Suppressed it is fine and handy as heck.

I’ve messed with a 300 blk some and it is fun suppressed but I haven’t shot anything with it.

If you are going to do it I say definitely get a suppressor too.

Three PSA pistol uppers here, one dedicated lower with the SBA3. Mine are 10.5" 5.56, 11.5" 5.56, and 10.5" 7.62x39. I like the pinned on FSB, and went that route on all. But that's personal preference.

Here's the 11.5" 5.56, my fave.




10.5" 7.62x39,

Nice!!!

I wouldn't consider that good advice at all. Stick with at least 9" or longer, ~10.5" is better. The very short barrels are a LOT louder, both suppressed and unsuppressed, and are also more finicky about ammo. Also, while the 300 is pretty efficient down to about 9" of barrel, you do give up a lot more with barrels shorter than that.

I've had good results with 9" and 11" 300 Blk pistol barrels, if I were starting over I'd stick with about 10"-10.5".

I was looking at the Saint yesterday. It has a blast deflector, that was kinda of an interesting feature.

Some stuff that may help you decide

especially if you reload

125 gr Lil gun loads, as an example, in longer barrels (18" range) run around 2400 fps and around 30k, and muzzle blast from this "group" is pretty severe in pistol ARs

loads using 300 BLK powder using bullets in 200 gr range using about 11 grs at 1000 fps run around 13k, significantly reducing muzzle blast.

loads duplicating 44 mag velocities run a bit hotter.

do you want to use it as a rifle or as a very efficient pistol? (high mag, capacity, better sight picture, trigger, and grip)

If you say so... I will run a 7.5 inch barrel when I build mine.. and you do whatever you want..

Saw a 12" Larue upper kit in 223. It seems to shoot very nicely.

I do what I've learned works best, and don't have to guess. A 7.5" 300 Blk barrel isn't any part of that.