I expect that is just a typo with the twist being 1 in 10" or 12", not 1 in 20.
; A 14" twist would work just fine with heavier bullets in 9.3, as it does in the .375 and the smaller .358's with their longest bullets.
: I wouldn't worry about Ruger as they'll get the twist right. I'm sure.
: Barnes "X" bullet require faster than normal twists, and more guns aren't rifled fast enough for the heavier ones.
: Too, some guns just don't like the old-style Barnes "X", however I've had exceptional accuracy with the blue coated 120 XLC in my daughter's .260 Rem, and the 160gr. Triple Shock Barnes outshoots all Nosler and Speer bullets in my 7mm Mauser.