It will be fine. Dead is dead. Their is no such things as "too dead".
I'd still hold off for a .308 though. As to the Prince Edward county 270 thing, I cant find anything about it, maybe you can. Heres the link to the hunting regs.
http://www.mnr.gov.on.ca/stdprodconsume/groups/lr/@mnr/@fw/documents/document/239852.pdf
The holder of a small game licence may not use a rifle of
greater calibre than .275, except a flintlock or percussion
cap muzzle-loading gun, for hunting small game in
the counties of Brant, Elgin, Essex, Huron, Lambton,
Middlesex, Northumberland, Oxford, Perth and
Wellington and the regional municipalities of Chatham/
Kent, Durham, the former regional municipalities of
Haldimand-Norfolk and Hamilton-Wentworth, Halton,
Niagara, Peel, Waterloo and York and the City of Toronto.