Looking for a good chambering for a new pistol lower. Thinking I have enough 223 type chamberings. 300 blackout? 7.62x39? What is a good choice for the short barrel?

Personally, unless I was going to run it suppressed all the time, I would go with a pistol round, simply because the .223, BO, or 7.62x39 are obnoxiously loud and have terrible muzzle flash / blast out of pistol length barrels.
I've got 2 in 5.56, one 7.5 inch, one 11 inch, and 1 300 BO with a 10.5 inch barrel...none of them are 'pleasant' to shoot without a can, even wearing ear plugs and muffs. I couldn't imagine touching any of them off inside a closed environment.
The 9mm, 10.5 inch, while not hearing safe by any means, is a lot more enjoyable to shoot with just normal hearing protection.

Next one I build will be a 6.5 Grendel.

I love my 7.5” Saint in 5.56. It’d be hard to beat it as a truck gun. I don’t think the noise and blast is any worse than my 16 5.56 with a birdcage.

I love the Grendel have three of them. Built-in upper 10 and a half inch barrel Grendel. It makes the same length barrel on a 556 and 300 Blackout seem whisper-quiet that thing was God awful loud.

Mostly agree. Just wish the LOP was a tad longer

I like to be different, so I would use a 450 BM bolt and make a 45 Win Mag. If you are going to supress it, the round is super sonic. I don't know how you would address the magazine issue.

I haven’t experienced the 11.5” 5.56 or the 9.5” .300 BLK to be obnoxious either. Haven’t tried either indoors or without ear protection, though.

Grendel is pretty good. Have you considered 350 legend?

I've got a couple of 5.56. A 10.5", and an 11.5".

For something different, I went with 7.62x39 with a 10.5" barrel. I chose that chambering for the availability and cost of ammo (a couple years ago). Also since I have a couple rifles in that chambering.

The 7.62x39 is nice. No regrets on that choice. 124gr does around 2150-2200 fps.

50 yard sight in,








Churched-up with some Magpul furniture,

Uh oh. You put it on your shoulder. You felon, you...lol

Y’all have heard of the point system and ATF’s new ruling coming out right? Get ready to pay a $200 tax stamp and SBR them. I figure that will change lots of folks ideas af what a good pistol caliber is.

Something modeled on the MP-5K in 9mm is looking much more interesting....

Oops.

Actually it's not on my shoulder at all.

To be honest, The AR pistol was an itch I had to scratch.

Now that I've scratched it, I'm not really shooting them much. In reality, I much prefer my 14.5" pinned/welded carbines for a useful shorty, in my world.

The whole brace deal is kind of A $hitty compromise to be honest.....my take anyways.

Given current events, I'm kind of in a tossup between SBR'ing the lower, and use a proper carbine stock......or rebarrel them to 14.5" pinned/welded, and move on. I don't really think I will ever have a purpose where an SBR/pistol would be an advantage over a 14.5" P/W'd

For a short AR, get a 5.56/223 Wylde and shoot federal fusion/gold dots for when it matters. You can practice with cheaper ammo and then load those for other than practice. The 62 grain will expand past 300 yards from a 10.3 at sea level.

Maybe not the best, but a 10mm seems about right to me. I’d forgo the brace and go with a tensioning sling.

Heard somewhere that they’re talking about an “approved” list of braces. Of course any such list can be edited at any time to futz up the works again, which is why I wrote Joe Manchin and suggested that Congress should look at this and not leave it to a bunch of unelected, unaccountable, agenda-driven bureaucrats. Also told him it was a crap idea in the first place too, of course, but thought that suggesting that it’s a bureaucratic power-grab couldn’t hurt. Gotta tickle these guys where they feel it most.