Lots of guys in BC shoot wild turkeys with .17 HMR. Regs just say 'rimfire' (as stated above). More like sniping than hunting I think, but it is a popular choice!
Very interesting. Always wondered about that clearly ridiculous shotgun only rule and why we can't hunt turkey with rifles. Head shots with the 17HMR or 22LR are gonna kill a turkey just as dead as a 12ga with 3.5" shells. Guess it's just rifles are more efficient and more hunters would fill their tags more easily than with a shotgun.