I fully concurr that the faster rate of twist will stabilize the longer (and normally) heavier Bullets. Remember that a 1 in 9 twist is faster than a 1 in 10 twist.

Now for the bad news:while a 1 in 14 twist will stabilize 50 and 55 grain bullets,(I've never shot 60 grainers in one) you don't want to go much heavier than that....you might get away with shooting 60 grainers in a 1 in 14 twist, but here's the rub.....there are several very good bullets that have such thin jackets that if driven too fast(RPMs) they blow up in mid air and never reach their target.....calculate the RPMs at close to 250,000!!!! The manufacturers warn you but in terms of feet per second. They do it this way because they think you don't have a brain to understand RPMs and centrifugal force!!

Here's the bottom line, if you really want a .22-250 and you want it to shoot primarily the 60 and 64 grain bullets, go with the 1 in 12 twist. But if you want to shoot the explosive pills from Sierra, Speer, and Hornady at serious high velocities, use the 1 in 14 twist because it will allow you to drive these serious little bullets at very high velocity without blowing them up from centrifugal force.

personally, I'd choose the 1 in 14 twist because if I wanted to shoot the heavier bullet, I should have picked the .243.