1-8 Twist is preferred in a 223 caliber
Tikka
Ruger
I believe Mossberg all run 1-8
55-77 gr projectiles are mainstream are they not ?
I have a Tikka T3, 223 Rem. 8" twist. Mine will not group the 50 or 55's less than about 1 MOA which isn't bad for a factory rifle. I tried the 60 Vmax's and the groups shrunk to under .5 MOA. I see posts where many claim that their 8" twist 223's handle the 50 and 55's very well; I don't dispute this; perhaps my rifle is just different and not the norm.
My 12" twist 223's (seven) all shoot the 50 and 55's extremely well.