We cannot recommend alteration of any pistol magazine to fit a rifle, sorry ... I suspect this is illegal to do in Canada.
There are your bold letters, lol.
The front lip of the magazine is indeed important, but as I have often informed people the correct way to deal with the front lip is too cut a groove across the underside of the bolt where it will make contact with the front lip.
Please see the bolt mod info and pics posted earlier in this thread.