Rimfire benchrest in Canada ? You will be disappointed...
A few years ago, there was a group of shooters that used to hold 4-5 matches every summer. Now, they hold only one rimfire match a year (they shoot a four IR50/50 targets match). It's being held in July, in the Eastern Townships, about 1 1/2 hour from Montreal.
As far as I know, there is no formal competitions in Ontario or Vermont. In N.Y., there used to be matches in Salem but I don't know if the club is still active.