AR-15 Caliber Options

pistol brace and a 10" 9mm upper with endomags

Great fun, easy to feed.

6.5 or 6.8, I've been looking at these I'm leaning towards the 6.5.
Also 7.62x39, cheap ammo I have a sks and enjoy it

Binary trigger is a great (and fun) way to turn money into noise. That means the caliber chosen should be as economical as possible. Start off with a dedicated 22lr upper. Yes, it'll work with your binary trigger.

Let me remind you that once you have your lower assembled, you can run whatever upper on it you want, including the uppers you already have. You're not building an AR. You're assembling a lower.

Since your in MI and already have a 450 BM, you could experiment with 350 Legend....

I’d go with a 6.8 or 6.5 also. If you ever find yourself in the northern zones, these are no slouch deer cartridges. If you like big bore, then 458 Socom but really one only needs one or the other of 458 Socom or 450 BM.

One AR cartridge that intrigues me for no particular reason is 17 Remington.

My RRA LAR-47 shoots cheap wolf ammo very well! I was amazed at my 100 yard groups with a 3X optic. I would strongly consider 7.62x39 as one of your options.

Do you reload?

K_Dubbya said:

Cant tell from the pic is that an AR-15 lower?

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Mine is a PSA 9mm specific lower that uses colt SMG mags. If I were building another one though I would probably use a normal AR15 lower and the endomag conversion magazines.

https://www.thefirearmblog.com/blog...-mean-arms-endo-mag-convert-5-56-pmag-to-9mm/

You could go 224 Valery or 7mm as well. There are a lot of options. Caliber choice would depend on intended use.

Ar-57

50 round magazines + binary trigger = ammunition induced poverty.

+1 on the .224 Valkyrie.
It is nice to have an AR15 with long range capability.
The valkrie uses the same BCG as the 6.8spc for your next upgrade.

.350 Legend.

10.5" DI Upper in 45ACP from Macon Armory - with SBA brace
Rudy makes them, with the mag block and stick mags, they are removable from your lower at any point to change calibers later on.
Can be shot indoors at any range, at the Pit since you're in the mitten, or really anywhere.
Love mine...230grain FMJ over 4.X grains of Titegroup...off to the races

.300AAC, pistol brace, 9" barrel:



Hit's harder than a .223/5.56 in the same barrel length, not as loud and all you're out should you decide to later change is a barrel. Brass is everywhere and in a pinch you can form it yourself.

Why not a precision rig?

Something like a 22" 6.5 Grendel or 224 Valkyrie with a big ol honking scope on it. Looks like you've got all the other bases covered.

A nice hefty lower with a good trigger would be nice to slap your other uppers on for load development.

CMMG Banshee upper with 9mm endomags.

More economical to shoot 9mm with a binary trigger. Much more reliable than 22lr. And good enough for shooting steel and knocking it down, but without the damage of 5.56.



Radially delayed blowback is much smoother than direct blowback, uses standard buffers so the same lower can be used with 5.56, and it suppresses better because the bolt does stay locked up until the carrier cams.

I have 8 ARs, 7.62X39, 5.56, 450 bushmaster and 300 blackout.

My favorite AR is my 10.5” 300 blk with sba3 brace.

It does way better with the short barrel than the others and if you reload, you can get really good performance with the lighter bullets and lil gun.

Yeah I know it’s universally accepted here to hate 300 blk and lil gun but my personal experiences differ.

Nothing like going from 110g screamers to 220g subsonic in the same magazine and never missing a beat.

I have three AR's two are identical 6.8 spcII's, the third is a 5.56 AR which I wouldn't own but for the ability to shoot cheaply and can feed should SHTF.

I like the 6.8 and feel it is the best cartridge for the AR, it has much utilitarian value.

K_Dubbya said:

I sure do.

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Then the world is your oyster! Find a use, then pick a diameter of your choice for the pearl. The case can come after.
All is predicated on use though.

357ARmax is better than the 350, by a wide margin. 6.5 G is a good one, I like my Valk and Bushy. My Blackout is sleeping under my pillow right now, whilst I wait for the coffee maker to finish.

We are both from Michigan and we have no 277 Wolverine!? Perish the thought!

What about a Bushmaster necked down to .243? Or .30?

I think I might set it as my dedicated lower. A nice, premium build out lower to set any upper on. At first I thought I would want a lower for every upper. Then I built three that are nearly identical. That's powder money... But for the Valkyrie it's nice to have a matched reciever set, mostly because its so pretty. Aero MfourEone, my new favorite set.

You did mention binary function, that screams rimfire or cheap fodder, but you have those...

Maybe a Patriot Brown furnitured twenty inch, irons only, a modern Minute Man Musket! For your party...

Hmmm. A conundrum for certain! The perfect "problem" to have!
Sorry I couldn't help.

Chuck R. said:

.300AAC, pistol brace, 9" barrel:

View attachment 852598

Hit's harder than a .223/5.56 in the same barrel length, not as loud and all you're out should you decide to later change is a barrel. Brass is everywhere and in a pinch you can form it yourself.

Click to expand...

where did you get that elastic for the mag, love that idea.

Robbins290 said:

where did you get that elastic for the mag, love that idea.

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I've seen them online, but any fun show will have them right next to the punisher engraved Glock back plates.

Robbins290 said:

where did you get that elastic for the mag, love that idea.

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Calibands and Sighthound sell them on Amazon.