A 14" twist should stabilize a 350 gr. bullet, so a 12" should also work. There is no such thing as being over-stabilized, so a 12" won't hurt anything.

It will be interesting to see if all this talk about bullet rpm affecting penetration is true.

No one has really adequately defined the parameters that affect linear penetration, besides the standard SD, PI, etc. Added to that the differences in penetration with seemingly similar shots on game, trying to mumbo-jumbo a reason for penetration as a result of bullet rpm is going to be a hard sell.

The rotational energy of a bullet regardless of its rpm is negligible compared to its linear kinetic energy, so I doubt there can be any noticeable effect on penetration, but who knows.

Penetration thru plywood, gelatin, wet phone books, etc. may prove something, but I doubt anyone knows what exactly it proves.

Who is able to shoot a thousand buffalo to prove any theory? Because Bubba dropped a buff with a geewiz bullet and a 6" twist doesn't mean crap.