Sounds like I would want a 12 twist at minimum and the 9 would probably be most useful.
I would mainly be using a 40 grain polymer tip of some flavor for maximum mist factor but don't want to paint myself in a corner if I want to go with a 55 grain bullet.
Yeah 9 or 12 would do it, 9 for surplus it gives the little 40 grainers a few more RPMs which increase the splatter factor!
