Subsonic 5.56/223

[aspangler]

Anyone have a subsonic 5.56/223 load that will reliably operate an AR? Cast or condom. Just looking to play a little. I have some that work in my bolt gun but with the fast pistol powder I have doubts about them working the action of an AR. Thanks guys.

[2wheelDuke]

I don't see it cycling a standard AR unless you do some modifications to the gun as far as the gas system, recoil buffer, and bolt.

[timspawn]

A suppressor might help too but as a general rule an AR will not cycle subsonic 223.

[Tackleberry41]

I played with it one day using trailboss, they worked as in the bullet came out the end and hit what it was aimed at. Cycle a rifle? Doubt that would happen no matter the mod, theres just so very little pressure to keep a bullet like that subsonic.

It does work but not very practical. Heaviest I could go with a 1-9 twist was 60gr, and it had to be a flat base spitzer, a boat tail shifts the weight forward and you have reduce the weight. You would be better off with a 22lr conversion bolt in it, it will cycle that way, faster 223 twist would allow use of the heavy 60gr bullets. I have 55gr mold, but just didnt figure worth the effort to mess with it.

[aspangler]

Oh well. It was just a thought. I figured it wouldn't work. I asked here because of so many knowledgeable people on this forum. Se la vie.

[JWFilips]

I'm shooting 3 grains bullseye (but in a bolt action) Very accurate but don't know if it will work an AR

[freebullet]

What kind of ar?

An ar with a short bbl on a pistol or sbr with an unregulated gas block might get you there. You would need the heaviest boolits that fit. Like the mp molds 227-75.

You can get a second buffer spring and trim it down to cycle lighter loads. They are plenty easy to swap out.

Do some searching on what port pressures it takes to operate the various sized ar configurations. Then look for powder options in cast loading manuals like lyman cbh3-4.

It depends on a myriad of factors if it will work. We'd need many more details.

[bangerjim]

I load subs in 223/556 for my bolt actions and they work great. Loaned some to some buddies at the range and they will NOT cycle thier ARs.

banger-j

[BK7saum]

To have any chance of cycling, you'd have to use a heavy bullet and a slow powder to have enough volume and pressure to cycle the action.

[Artful]

I have only seen one AR cycle with subsonic ammo (commercial load w/ 77 grain pill) and the rifle had a 1:7 twist and only worked for half a dozen round then wouldn't cycle - until you cleaned it spotless and re-oiled it, then good for another half dozen or so. And never did that with the two AR's of mine I had that day - just his.

I used to say get the 22LR submunition parts and train with 22LR but that's not really an option today now is it.

[dkf]

You may be able to get a cycling subsonic with the bullet in the link below if you use the right powder, a carbine gas system and open up the gas port in the barrel. Even then you may have to use a light buffer, carrier and etc for it to work. Not worth it IMO.

http://outlawstatebullets.com/12.html

[Tackleberry41]

The pressure required to cycle a gas weapon is usually pretty specific. To get a good subsonic load, its usually the opposite of that. Trail boss works good, but doubt theres much pressure by the time it gets to the port. You go using a powder to get enough gas, well now your dealing with muzzle blast, or even the blast thru the gas system. Friend was running some subsonic 300 blackout thru his new AR last time we were shooting, yes it was definitely quieter than normal, but still plenty loud. I was testing some subsonic thru a bolt gun, I had tried couple different powders to get that blast down, the bullet down range was louder. The 300 is a balance of noise and pressure so the rifle will cycle.

[30Carbine]

I do this with my niece she's 8 now. once you do this you can never shoot standard from it again.

you cut 4 to 5 coils from the buffer spring. also use the lightest buffer you can buy, or make one on your lathe.
use a ar15 bolt not m16 bolt. ar15 bolt is lighter
drill the gas tube hole in the barrel out to twice the size of the original. carbine length with 16" barrel.
drill the gas block. I use an adjustable and drilled
I use magnum primers and BE. don't ask for the load you will not get it. they crono at 1000-1100. 1-8 twist with a 225646.
REILIABLE NOPE that being said if the bolt is wet and I mean dripping wet it will run a mag full. then stop clean and repeat.
she is coming up next weekend we are going to try her on one of the we will say real ones so we will see how it goes.