300 AAC Blackout (7.62×35mm)

[robertbank]

I have a friend down in Washington who is looking into this calber and building an AR for it. He has asked me about using cast bullets. Specifically he was interested in using 200+ gr boolits at sub sonic speeds.

Since the cartridge almost mirrors the 7.62x39 in performance I think his idea is doable. Has anyone on this forum had any experience with the 300 Blackout cartridge. I have loaded and have some effective loads for the 7.62x39 using cast boolits. None however have been shot sub sonic. Given the case size I would think a light load of Unique or Little Gun might be ideal.

Thoughts

Bob

[Rustyleee]

If you go to youtube, look up "the black rifle channel." The shooter there, Alan shoots his Blackout with cast bullets but is not happy with the results. He said lube was really blown into the gas system, but that IS using a suppressor which increased back pressure and they weren't as accurate as the jacketed rounds.
I think a dedicated cast bullet shooter could improve on those results as long as rapid fire was kept to a minimum.

[TreeKiller]

I just got one and have shot nothing but cast in it. Got the new Hm2 155g mold but have shot some Lee 180g and 311299 HP 209g also. I do not have a heavier Boolit yet to try. Have not put it on paper but everything i have shot seem to be very accurate so far.

[Jupiter7]

For subsonic only, I'd suggest 220gr minimum. Lil gun is iffy in certain guns cycling the action. Unique will not cycle or even eject a fired case. I use the accurate mold 31-241E, it is very similar to the noe 247gr mold. I cast mine out of range scrap lead, air cooled, lubed with bens red sized at .310. Be aware that certain mags do not like feeding the blackout. Also for better luck, try reloader 7, 5744 and my favorite aa1680. Also think of it more like a magnum pistol round.

I also shoot tons of cast supersonic boolits. The lee 312-155 , over 15ish grains lil gun is perfect for fast twist AR's.

[Moonie]

We have 2 of these uppers. I load the Lee 312-155gr over 15.3gr H110/W296 and a 245gr Accurate Molds boolit over 12gr Reloader7. These cycle perfectly in both uppers.