Optimal calibers for cast AR ahooting

[Wolfdog91]

Is your opinions what are some if the more optimal calibers for casting on the AR platform ? Seems that a few calibers like .300 blk and .458 SOCOM just plain work with cast out if an at while somthing like a .223 is A bit more finicky. So just by their nature what's are some of the better calibers for casting in the AR platform?

[popper]

308W, about anything 30 cal and up. except the 350 legend.

[John McCorkle]

More mass conducive calibers?

I've only tried with 300 BLK after alot of seeing others trial and error with alot of success in the round.

300 BLK is great for cast in all platforms I've tried it in.

Seems like calibers that require alot of velocity and high pressures to add alot of stress to the system and projectile...like plugging an amplifier up to an off tuned guitar. It may sound good or ok at low volume but crank it up and you can really tell how off tune it is or the details of how the tone doesn't sound right

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[Texas by God]

7.62x39 was easy for me. .300 BO wasnt. That's the limit of my AR casting experience. YMMV.

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[sutherpride59]

Popper, what would be wrong with the 350 legend? I thought it would be a good cast round but I have read much about it.

[Lloyd Smale]

300 bo hands down for a factory chambered round. A few wildcats fit the bill too. 762x39 is hit and miss. Some guns (like the one I had) were way to finiky even with jacketed reloads. Heck even factory steel bullet wolf. But if your gun runs well it should be no more work to find a load then in a 300 bo. Now an ar10 308 is a different animal. You need to be able to run it at least 500 fps faster then the bo or 39 just to make it run. Lots harder to find accuracy at 2500 fps then it is at 2000 fps. Ive shot cast in mine but had to settle for minute of man accuracy. MOA just wasn't happening with any load or bullet I tried that would run the gun. You run into the same walls as you will encounter trying to shoot full power cast loads in an 556. but ill give you this advice. Get a BO buy yourself a rcbs 130 spitzer gas check mold. Cast them hard, pc them, put the check on! and start with 19 grains of 110 and move up slowly till you find a sweet spot. If you have a good gun that load will shoot. I have 3 bos from a 7 inch to a 16 and even the 7 inch gun will do 1.5 inches at 50 yards the 8.5 slightly better but those guns have red dots. The 16 will shoot 10 shot groups under 2 inch at a 100 (it has a scope) Not moa but plenty good to hit something out past even 200 yards. Sweet spot for my gun was 20 grains but anything from 19 to 22 shot real well.

[dverna]

If I had to shoot cast out of an AR15, I would pick the .300 BO. It seems the right fit wrt bullet size, and case capacity. The .300 offers a deer round but I would not use an AR to hunt with anyway.

Brass can be made cheaply with some investment in time.

I bought a mold for the 5.56 but have never used it as I found a source for Hornady 55 gr SP'S at $7/100. Those bullets go on sale a couple of times a year. 6000 bulk pack. For coyotes and paper they are OK. Should work on two legged varmints if it comes to that, but the .300 would be better.

There is a .358AR round that would be of interest. It can be made from 5.56 brass. .350 Legend brass is proprietary and that would be a negative for me.

[mehavey]

So far in an AR action:

223/556
308 Win
350 Legend
50 BeoWoooof

All have served me well with cast/multiple moulds each/Lyman#2(gas-checked)/thin ALOX/pretty much near-full velocities/spotless bores.

[Burnt Fingers]

My luck so far with the 300 Blackout has been a failure. I've gotten two new gas check molds. I'm going to try some gas checked bullets.

The four different plain based bullets I tried all failed. Even the 235 gr MP hollow point.

[sundog]

Yes, 300BO works good with cast, especially GC'd and PC'd.

I am rather surprised that 7.62x40WT (12 twist) and 300 Ham'r (15 twist) have not caught on better with the cast boolit folks. Both are very easy to get shooting with cast. Onliest thing needed is a barrel swap and make (or buy) some brass.

[JMax]

Two 7.62x39 ARs using Lee bullet sized to .314 Using IMR4227 at 14.5 gr to 16 gr shoot these with abandon with no malfunctions.

[rockrat]

Don't forget 450 bushmaster and the 50 beowulf

[odfairfaxsub]

I cast for 50 beo, 450 Bush, 300 blackout subs, ar10 308. Ar15 will deff cast for 762x39 according to my friend John

[fastdadio]

308W, about anything 30 cal and up. except the legion.

Strange you would say this about the 350 Legend. Personally, I had no interest in the AR platform until this cartridge was developed.
But then, I'm one of those guys that live and hunt in a restricted rifle zone that it was developed and sold for.
A 9x43mm cartridge, driving a 180 gr at 2200 fps. is in my opinion, the ultimate pistol caliber carbine.

[popper]

Legend appears to be hard to find moulds that work good. Converting brass is a pain. Doesn't make sense unless required.

[gpidaho]

I have an AR upper, a bolt action Ruger and a Handi rifle in 300 blackout. A Noe 129gr. SP gas checked and powder coated over 17gr. LilGun works well in all of them. I have messed with cast 223 loads but find it more trouble than it's worth. Gp

[44Blam]

Strange you would say this about the 350 Legend. Personally, I had no interest in the AR platform until this cartridge was developed.
But then, I'm one of those guys that live and hunt in a restricted rifle zone that it was developed and sold for.
A 9x43mm cartridge, driving a 180 gr at 2200 fps. is in my opinion, the ultimate pistol caliber carbine.

YES.
But pistol caliber carbine is a bad term. This is a rifle cartridge for sure. The other cool thing is a 9mm boolit (gas checked and properly lubed) can be sent at about 2500 fps out of this platform...

[44Blam]

Legend appears to be hard to find moulds that work good. Converting brass is a pain. Doesn't make sense unless required.

I drank the coolaid because I got an upper with BCG for under $300... I also spent a bit on brass, dies, etc... Those cases are not gonna be 'lost'...

[fastdadio]

I drank the coolaid because I got an upper with BCG for under $300... I also spent a bit on brass, dies, etc... Those cases are not gonna be 'lost'...

I bought a hundred rounds of factory Win. fmj. to get me going. At .50 cents a round, I thought it was reasonable, and plan to buy some more. I got the lee dies, and a detachable brass catcher that mounts on the pic rail. Never used a brass catcher before. I think I'm going to like this thing. The only thing holding me back from the bench is the non-availability of small rifle primers. Never had need for them until now.
Why do you say 'pistol caliber carbine' is a bad term? I chose that term for a reason, and called it a 9x43 instead of 350 Legend. Seems to me that this new cartridge confuses a lot of people. When compared to other rifle loadings, it does come up a bit short, but when compared to a pistol cartridge, it's the hot new ticket.
Compare it to this;
https://en.wikipedia.org/wiki/.375_Winchester

[Burnt Fingers]

Legend appears to be hard to find moulds that work good. Converting brass is a pain. Doesn't make sense unless required.

The Legend was never intended for you to form brass for it. It's a bit larger in diameter than the parent 223 case.

Just buy some ammo or brass and go.