As near as I can tell with a tight patch, my new ruger 350 mag is a 1 in 12" twist. It is also 1/8" longer in the mag box than my 700 classic. Ruger holds 4 down and feeds crf slick. Haven't been to the range yet, but this could open up the 250 gr. options. Seems to be a good package.
Dan

Davidson has some special run .350 Rem mag Rugers and they claim that they are 1 in 14†twist. CP.