The Sierra 190 is designed to work in a slower twist, but a 1-12 won't fully stabilize a 168 Berger VLD, 165 or 168 Tipped TSX, or even a 165 Nosler Ballistic Tip in all hunting conditions. And yes, Bryan Litz's latest research demonstrates that it's better to over-stabilize than marginally stabilize.

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck