Twist rate for .223 cast bullets

[Larry Gibson]

Larry,
Would a projectile from a 1:8 twist, 10.5" barrel at about 1900-2000 FPS stabilize?
Projectile is RCBS 22-055 55 grain semi point.

That bullet should stabilize at 200 - 300 fps from that firearm.

Larry Gibson

[cpy911]

Great! What about accuracy at 100 yards?
I have a 16" 1:9 twist barrel shooting the same load getting 2 MOA. Hoping for something similar from shorter barrel SBR I am doing.

That bullet should stabilize at 200 - 300 fps from that firearm.

Larry Gibson

[Shiori357]

Try to built AR upper specially shoot for cast load, mainly 100 yard target shooting use optical sighting, shoot from bench rest.
Accuracy goal will be 2 MOA or better and semi auto loading should function as conventional AR.

Thinking to get 1-14" twist 20" barrel, use full floating hand-guard.

Cast boolit, RCBS mold 55gr sized to .255, Honady Gas check on with lube sizer, alloy is straight wheel weight.
H4895, 14.1gr (1800fps), 14.5gr (1850fps), 14.9gr (1900fps), 15,3gr (1950fps), 15.7gr (2000fps) with 3/4 gr Dacron filler.

Auto loading function probably need to accelerate to 2300fps range, hope 1-14 twist capable to handle slower rpm for W-W cast boolit.

Should I try slower burning as H4350 or faster burning H4198, if above charge would not work.
If so what grain to start with ?

Appreciate experience forks recommendation.
Shiori

[Road_Clam]

Try to built AR upper specially shoot for cast load, mainly 100 yard target shooting use optical sighting, shoot from bench rest.
Accuracy goal will be 2 MOA or better and semi auto loading should function as conventional AR.

Thinking to get 1-14" twist 20" barrel, use full floating hand-guard.

Cast boolit, RCBS mold 55gr sized to .255, Honady Gas check on with lube sizer, alloy is straight wheel weight.
H4895, 14.1gr (1800fps), 14.5gr (1850fps), 14.9gr (1900fps), 15,3gr (1950fps), 15.7gr (2000fps) with 3/4 gr Dacron filler.

Auto loading function probably need to accelerate to 2300fps range, hope 1-14 twist capable to handle slower rpm for W-W cast boolit.

Should I try slower burning as H4350 or faster burning H4198, if above charge would not work.
If so what grain to start with ?

Appreciate experience forks recommendation.
Shiori

Can't help you with cast bullet twist rate knowledge as that's above my pay grade. I can help with your powder selection. I advise you don't use 4198 as it's a very fast powder and you will most likely end up with your AR's gas system and action "short stroking" This causes stovepipe jams. Many excellent powders for AR's is W748, Varget , 8208XBR, RL15 and 4895. Generally speaking heavier bullets favor slower burning powders, and vice-versa. Good luck