Since he is in Ontario the specific "hunting" regulation regarding semi-automatic (non-restricted center fire rifles) reads:"Under the Criminal Code of Canada you can not possess any clip/magazine that holds more than 5 shots for a semi-automatic center-fire non-restricted firearm unless that clip/magazine has been specifically exempted, pursuant to the Firearms Regulations."So if a magazine IS exempted from the 5 round limit then it would be "legal" to hunt with it attached to your center-fire rifle. You just might save yourself a huge headache by sticking with a 5 round mag. While you might be "right" if you run into a CO while on a hunting trip who couldn't tell you what was approved or not you might find yourself missing a good chunk of your trip while things got sorted out.