AR pistol barrel twist rate and subsonic loads?

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Wiley300
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AR pistol barrel twist rate and subsonic loads?

Post by Wiley300 »

I'm new at this 300BLK game but have loaded my own ammo for years. I have an AR pistol with 9" barrel and 1/8 twist. I want to load some 220gr subsonic loads as that is the only heavy bullet that I currently have on hand. Will my barrel stabilize these bullets?
Wiley300
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Re: AR pistol barrel twist rate and subsonic loads?

Post by Wiley300 »

After more searching the site I have found my answer and my 1/8 twist barrel should be fine. Happy, happy! :)
BJK
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Re: AR pistol barrel twist rate and subsonic loads?

Post by BJK »

(edit:It seems that you post faster than I do. )

The question I asked myself is, "If it won't stabilize them what was that barrel built for?". I couldn't come up with a good answer.

I'm new to the 300BLK also, but from all that I've read I'd say your barrel is in the general area of what is required if it's a lead bullet. Will it stabilize a copper 220gr bullet? I don't know. But my barrel is a 1:7 and it's said to be what's required for 220 copper. But lots of this stuff isn't magic and there is a range within which bullets work.

I would check some load data and see what was used for the twist rate in the bullet launcher. That's where I got my information. I welcome folks double checking me and being corrected if I'm wrong. That's how I learn. If you go into the handloading section you'll find all sorts of data, or just do a 'net search for 300BLK load data and you'll come up with manufacturer data.

But ultimately you won't know until you load some.
Wiley300
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Re: AR pistol barrel twist rate and subsonic loads?

Post by Wiley300 »

I loaded 30 rounds (3 different loads of Shooters World Blackout powder) with 220gr Hornady round nose Interlock and will be headed over to the range on my place around noon. Hopefully the bullets will stabilize and I can shoot suppressed after verifying no bullet tumble.
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dellet
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Re: AR pistol barrel twist rate and subsonic loads?

Post by dellet »

Bullet length is #1 thing to be concerned with, then bullet shape then density. Some shapes are more stable than others.

In general a 1/8 twist is good for bullets up to about 1.65” long, then the other factors will come into play.

I shoot that bullet in a 1/10 with no issues.

As long as loaded to the correct length you will be fine. Too long and it can jam.
300 Blackout, not just for sub-sonics.
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