Oops. I may have misunderstood your post. Evidently Remington has sold .223 rifles with 1 in 12 rifling. Wise of you to have recognized that. I googled the topic and found some people who were unsatisfied with their Remington 700s for that reason.
I had a Colt H-bar which came with a .22LR adapter. It had a 1 in 7 twist which is way faster than standard .22LR barrels.
It was a beautiful rifle and was also extremely accurate with all .223 ammo. The real surprise was it handled .22LR ammo perfectly. That fast twist did not seem to harm accuracy at all.