Here is what the Ontario Regs say for small game.
Firearms
In an area where there is an open season for deer, moose
or black bear, if you are the holder of a small game
licence you may not possess or use a rifle of greater
calibre or projectile power than a .22 calibre rim-fire rifle
chambered to .22 short, .22 long or .22 long rifle or shells
loaded with ball or with shot larger than No. 2 shot (or if
using non-toxic shot, you may not use steel shot larger
than triple BBB steel shot, or bismuth shot that is larger
than double BB bismuth shot), unless you possess a valid
licence to hunt deer, moose or black bear as the case may be.
The above does not apply to the holder of a small game
licence, hunting small game only south of the French and
Mattawa Rivers during an open season for deer that is
restricted to the use of bows.
You 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, Haldimand-Norfolk, Halton, Hamilton-Wentworth,
Niagara, Peel, Waterloo and York and the City of Toronto.
Furbearing Mammals
If you wish to hunt raccoons at night, you must carry your
licence to hunt raccoon at night and your Outdoors Card
with a small game licence. You must also be accompanied
by a dog licensed for raccoon hunting. You can only use a
.22 calibre rim-fire rifle chambered for the following
cartridges: .22 short, .22 long or .22 long rifle. Raccoon
night hunters must have their guns encased while in the
vehicle. A licensed night raccoon hunter may use a light if it
is not shone from or attached to a vehicle or boat.