twist rate?

[sureshot2040]

whats the twist rate of a new .223 pro hunter barrel??
my cousin has one and it will shoot everything from 45gr wwb hp to 70 hornady amax within one inch of each other at 100 yards
but when he goes up to the 75gr amax it doesnt even hit the 16inch by 16inch target paper
we figure it just cant stabilize that big of a bullet
btw my handi rifle in the same caliber wont hit paper with that bullet either tho it shoots 55gr vmax sub moa at 100 yards
thanks
sureshot

[Catfish]

To stablize the 69 or 70 gr. bullets you need a 1 in 9 twist. Most .223 are 1 in 12 which will do well with bullets up to 55 gr. I have a .22-6mm I just had built for the 80 gr. Serria bullets and it has a 1 in 8 twist in it. Personally I like to use 50 gr. bullets in the .223 and .222 mag. and 55`s in the .22-250. Seem to me to be the best weights for the case capasity of the rounds.