Not sure if I phrased that correctly.

I'm tossing around the idea of exploring a caliber other than .223 for my next builds.

Using a standard AR15 lower (marked Cal Multi) what calibers are able to be used with it?


Bonus question, what calibers do you suggest and why for a non-.223 AR15? I know it's subjective, but I'm just looking for information about the different options.

What caliber is fun? What's just cool to have? What's expensive? What's just dumb?

The gun's purpose will not be anything in particular...just looking to expand my horizons a bit.

.17 Mach 2
.17 HMR
.17 Winchester Super Magnum
.22 Long Rifle
.22 Winchester Magnum Rimfire
.17 Mach IV
.17 Remington Fireball
.17 Remington
.17×223
.17×204 Ruger
.17 Tactical
.19 Calhoon
.19×223 Calhoon
.20 Tactical
.20 Practical
.204 Ruger
.20 PPC
.20×6.8
.20 LBC
.219 WASP-C
.222 Remington
.223 Remington
.223 Remington Ackley Improved
.223 BoZ
.22 PPC
.22 LBC
.22 Nosler
.224 AR
.22×6.8
.243 LBC
.223 Winchester Super Short Magnum
.243 Winchester Super Short Magnum
.25 Winchester Super Short Magnum
.25-45 Sharps
.25×6.8
.257 Bobcat
.264 LBC
.270 AR
.277 Wolverine (6.8×39mm)
.30 Carbine
.30 Herrett (.308-6.8)
.30 American
.30 Remington AR
.300 OSSM
.300 AAC Blackout (7.62×35mm)
.300 Whisper
.300 Winchester Magnum
.300 Sabre
.30 Coyote (30×40)
.30×6.8 (BHW)
.32 ACP
.338×39
.35/40
.35×44
.338 Spectre
.357 SIG
.357 Automag
.358 Yeti
.375 Reaper
.375 SOCOM
.40 S&W
.410 Shotgun
.44 Remington Magnum
.44 Automag
.440 Corbon Mag
.45 ACP
.450 Bushmaster
.458 SOCOM
.475 Tremor
.499 LW
.50 Beowulf
.50 Action Express
.640 Express Magnum
5.45×39mm
5.56×42mm (5.56-6.8)
5.56×45mm
5.7×28mm FN
6.5×40
6×45mm
6×6.8
6mm Hagar
6mm PPC
6mm AR
6mm AR Turbo
6mm Dasher
6mm Fat Rat
6mm Grendel AI
6mm PDK
6mm BR
6mm BRX
6.5mm BRX
6.5×6.8
6.5mm Grendel
6.5mm Patriot Combat Cartridge
6.5 BR
6.8×39mm (.277 Wolverine)
6.8mm Remington SPC
7×40
7mm SCAR
7mm BR
7mm Valkyrie
7.62×24mm
7.62×37mm Mustang
7.62×39mm
7.62×40mm Wilson Tactical
7.92x33mm Kurz
9mm Parabellum
9×23mm
10mm Auto
10mm SOCOM


... I might have missed one or two.

You could throw a 50bmg upper on there, but it’d be single loading. Fortunately, I know a local range you can shoot it at.

Far too many to list if your get into all the wildcats most folks never heard of.


For example, everyone now knows the "300 Blackout"... the 30/221. But there are also .25, 6mm, 6.5, 7mm, 8mm versions of just that one alone.


The list above has a few AR-10 sized rounds, not AR-15.

And that "30 Herrett" one is news to me and a puzzler. Why would you name it the same as something that already exists? Just add "AR" to it? Why go with an intentionally confusing name? It was pretty F'ing stupid when when Remington did it with the .30 Remington AR (we saw how well that one did). And while I'm ranting about names.. "25-45 Sharps"? Neat cartridge, but you couldn't have come up with a worse, less "AR" sounding name. It's an AR for christ sake, "tacticool" sells, why make it sound like a buffalo round. Why not call it a musket.

Ooookay then...that's a lot, thanks Rogue.

quote:

Originally posted by cas:
Far too many to list if your get into all the wildcats most folks never heard of.


For example, everyone now knows the "300 Blackout"... the 30/221. But there are also .25, 6mm, 6.5, 7mm, 8mm versions of just that one alone.

Ha! You guys are killin me.


What's a fun caliber to build around? Maybe my one requirement is for it to not be super expensive to buy the parts, or hard to find the ammo.

quote:

Originally posted by RAMIUS:

quote:

Originally posted by cas:
Far too many to list if your get into all the wildcats most folks never heard of.


For example, everyone now knows the "300 Blackout"... the 30/221. But there are also .25, 6mm, 6.5, 7mm, 8mm versions of just that one alone.

Ha! You guys are killin me.


What's a fun caliber to build around? Maybe my one requirement is for it to not be super expensive to buy the parts, or hard to find the ammo.

I hear 5.56 is a fun alternative in that platform. Ballistically, it’s very similar to .223, and doesn’t require extensive modification to the bolt, barrel, or magazines.

I already have one chambered in 5.56 AND one chambered in .223. It's hard to tell them apart.

Have seen one in 22-250, but can't recall the manufacturer.

300BO & 6.8SPCII would probably be my 2 alternates.

I've always been tempted by .50 Beowulf.

quote:

Originally posted by RAMIUS:
I'm tossing around the idea of exploring a caliber other than .223 for my next builds.

The gun's purpose will not be anything in particular...just looking to expand my horizons a bit.

The greatest benefit of a different caliber requires your defining what it will do better than 223.

Do you want greater accuracy?
Lower wind drift at distance?
Greater terminal energy?
Do you plan to hunt, and if so, which animals?
What kind of optics do you want and are willing to pay for?
Do you hand load?
Are you looking for a short, regular, on long length barrel?
Will you suppress the gun?
What barrel life in rounds do you find acceptable?
Do you have a preference for subsonic or supersonic loads?
Are you willing to use bolts and magazines different from those used in a 223?

300 blackout suppressed in my favorite alternative cartridge.

6.8 SPC is fun for a minute. I killed 3 deer with the cartridge.

I have no interest in other cartridges at this point. I like cheap ammo when it comes to ARs. I don't like hunting with them either. They are bulky, metal is louder than wood or composite, and bolt guns set up for hunting are generally lighter.

quote:

300 blackout suppressed in my favorite alternative cartridge.

a 300blk ar-pistol will be my next gun.

quote:

Originally posted by PorterN:

quote:

300 blackout suppressed in my favorite alternative cartridge.

a 300blk ar-pistol will be my next gun.

Working on one now, have everything but the lpk.

300 Blackout, simple change.

9MM, cheap fun.

Maybe 458 SOCOM after that.

357Sig sounds like a fun one.

quote:

Originally posted by Excam_Man:
300 Blackout, simple change.

9MM, cheap fun.

Maybe 458 SOCOM after that.

This gets my vote. Exactly what I was thinking.

quote:

Originally posted by RichardC:

quote:

Originally posted by 2012BOSS302:
357Sig sounds like a fun one.

Who makes those uppers/lowers/complete carbines?

I don't know if anyone offers a complete .357 Sig AR, but there are a few manufacturers, like Quarter Circle 10 and Macon Armory, who offer .357 SIG AR parts (namely barrels as everything else can use .40 parts).

You can use either RRA .40 stick magazines or Glock 357/40 magazines, depending on the lower receiver or magwell adapter you go with.

Here's a thread from last year with ARMT Man's .357 Sig AR: https://sigforum.com/eve/forums...0601935/m/2540013614

fritz asked lots of good questions. Personally, I have built up and diversified the caliber options the past 15 months. I have added 10.5" pistols in 9mm, 300BLK, 7.62x39, and .223 Wylde. 16" rifles in 6.5 Grendel and 6.8 SPC.

Right now I can't decide what to build next, likely dedicated .22LR, maybe .357SIG or 10mm, possibly 45ACP. 458SOCOM interests me, but right now I'm kind of into reloading mode as winter approaches and a new 100yd indoor range opened up 5 miles away from my house

It doesn’t meet your cheap ammo requirement, but .458 SOCOM is one fun AR to shoot...

I mean what’s not to like about a big bore AR?

And with factory ammo available from 200gr to 500gr, there are a lot of options...