Going to be running a wide variety of ammo with my hand loads from 40-75 GR and in a .223 / 5.56 1:12 or 1:14 simply won't stabilize those heavier weights. If I was shooting lighter pills then yes those twist rates would work in this caliber ( well .223 Wylde is technically a chambering) but for what I'm after then no ,not optimal at all.
And once the only thing really moving on an ar is the bolt carrier group which ,yes the recoil impulse is different and takes getting used to to ,it's actually not super hard to get sub MOA out of a well built one. Mainly because every thing else on it