Caliber for pistol build?

[Swampfox]

[Wheelhorse]

300 Blackout

Unlike a 9mm it uses standard parts.
Unlike the 5.56 cartridges, it uses pistol powder so a complete burn in a short barrel will happen.
It is easily loaded subsonic.

[Kilco]

Hmm for a 7.5" barrel and plinking I'd go with a 9mm.. for a truck gun I'd go 300 blackout (even hand loading it's a relatively expensive cartridge to plink with). 7.5" barrel narrows the options a bit.

If you go a bit longer barrel then you have a couple more options.. 7.62x39, 5.56 and Grendel you can get 1k rounds of steel case under $200 with a little shopping, but you will want at least a 10.5" barrel at that point.

[depletedyourcranium]

9mm if you're buying all new parts from scratch, but if you already have a lot of .223 stuff like mags, BCGs, standard lowers, I would seriously consider .300 Blk.

[Sixoeight]

9mm all day long. Obviously the recoil is low on all these choices but with 9mm it's like a lethal pellet gun.

I could go on all day but I'll just add one more point.

$0.16 a round

[Swampfox]

I was thinking 9mm, 40S&W, or 45 ACP. The issue is at that point has to be a pistol upper from what I understand. I probably have 20-35k 5.56 rounds I have reloaded sitting around. Always have to be prepared. I would do a 300BO, but as you stated to just have fun with kind of expensive, and I already have a 9in AR pistol in it.

[Texas]

I really like my 6.5 Grendel pistol and am hunting with it more and more

[Sixoeight]

I was thinking 9mm, 40S&W, or 45 ACP. The issue is at that point has to be a pistol upper from what I understand. I probably have 20-35k 5.56 rounds I have reloaded sitting around. Always have to be prepared. I would do a 300BO, but as you stated to just have fun with kind of expensive, and I already have a 9in AR pistol in it.

You can run a standard lower in a pistol build for 9mm you just need a magwell adapter. In the picture I posted it is a PSA standard lower with a Stern defense magwell adapter for Glock mags. I went this route so that I can just build a 5.56 7.5 upper one day and swap baxj and forth as needed. You simply swap the uppers and install or remove the magwell adapter.

Nothing wrong with 300blk it just doesn't fulfill any role for me that 9mm doesn't and the ammo costs 5 times as much. I wouldn't turn up my nose at one but I also wouldn't want to feed it for plinking.

[montana]

The problem with short 5.56 barrels is the ear shattering muzzle blast. You just have to ask any Vietnam vet who ran one. You may have to ask them twice when they respond, huh, what did you say?

[hootie6828]

I have been pondering this myself and the conclusion that I have come to is if you plan to hunt with it, 300blk, as a plinker 9mm seems really hard to beat. I have also been considering 45acp as it's one of my favorite rounds and I reload alot of it. Swampfox, since you already have a short 300, it would definitely have to be 9mm or 45acp, I have never been a 40 fan. There is simply nothing a 40 can do that a 9mm or 45 can't do as well or better IMO.

[AZHTfreak]

Do a 9 with Endomag pmag inserts. No mag block required...!
Bought a 3pak and they run flawlessly for me so far with 700 rds downrange across the 3 with 115, 124 FMJ, 124, 147 HST JHP. PSA 10.5 upper, G-9 Hybrid bolt, fleaBay blast diverter, plain ol AP pistol lower, H3/CAR spring with 5 quarters in the back. LRBHO every time bonus. I was pleasantly surprised, it's fun and cheap, 1-2 MOA @ 75yds = DRT...

~$600 in with a Romeo5 RD.

https://www.meanarms.com/products/detail/endomag-9mm

[FRB6.5]

Do a 9 with Endomag pmag inserts. No mag block required...!
Bought a 3pak and they run flawlessly for me so far with 700 rds downrange across the 3 with 115, 124 FMJ, 124, 147 HST JHP. PSA 10.5 upper, G-9 Hybrid bolt, fleaBay blast diverter, plain ol AP pistol lower, H3/CAR spring with 5 quarters in the back. LRBHO every time bonus. I was pleasantly surprised, 1.2 MOA @ 75yds = DRT...

https://www.meanarms.com/products/detail/endomag-9mm

That's pretty slick. Could seem them adapting something similar for large frame mags for wildcats that are too big for a small frame but too short for reliable feeding in an AR10.

[AZHTfreak]

Oops, not 1.2 moa, 1-2 moa, my fumble fingers on a dumbarse phone... Some have had feed issues with JHP, not me with ~150 rds. H3/CAR spring has been a really soft shooter for me. Don't know if meanarms is thinking about an AR-10 mag insert though.

[Sixoeight]

The endomag would be more attractive if the ejector was metal. Maybe it works fine, just seems like metal would be the obvious choice over plastic. I do hope they come out with a metal version, at that point I would be on board for sure! I don't have LRBHO on my adapter which isn't a big deal but is a perk of the Endo.

[AZHTfreak]

Approximately 233 rounds through each Endo mag insert. Meanarms has a lifetime warranty, if it fails they'll replace for $0. How many rounds do Glock/Colt mags last? Plus the cost of the magwell adapter? Just doing the math. Had me at lifetime warranty. I understand YMMV...