Im pretty sure that you get 3 rounds for shotguns, 5 rounds for centerfire semi auto, 10 rounds for rimfire. In ontario we also have a caliber/shot size restrictions. No buck shot larger than #1 or bullet over .275 cal. when its not a big game season or you dont have a license for that game.
Technically even target shooting with your .270 on crown land in July in illegal in ontario. I found that out the hard way, luckily the conservation officer was a good one.
Let's beat this dead horse again.
Shotgun, 2 in the magazine and 1 in the chamber max for all hunting in Ontario.
Centerfire, they follow the Federal firearms laws and all their exceptions, if a 10rd pistol magazine in a semi auto rifle is legal you can hunt with it in Ontario.
Rimfire, they follow the Federal firearms laws and all their exceptions, a 100rd drum mag can be used for hunting with a rimfire in Ontario if legal by Federal Firearms laws.
"No buck shot larger than #1 or bullet over .275 cal. when its not a big game season or you dont have a license for that game"
This one you are mixing up regulations completely. You cannot use anything larger than #2 Lead shot, BB Bismuth or BBB for steel for small game when there is an open big game gun season unless you have a license for that big game. You cannot use shot smaller than #1 buck for hunting big game in Ontario and when using shot no shotgun smaller than a 20ga (yes, 410 slugs are legal). Also, the .275 cal regulation is a maximum limit when hunting small game in only the listed specific municipalities, I can shoot coyotes with a 50 BMG legally where I live and I live in Ontario.
"Technically even target shooting with your .270 on crown land in July in illegal in ontario. I found that out the hard way, luckily the conservation officer was a good one. "
This one is also not correct. You have to look at your municipal bylaws as well as hunting regulations. You can target shoot on Crown land with any rifle as long as there is no specific regulation against it for that specific municipality or parcel of land. In the Ottawa Valley you can sight in your rifles on Crown land all day long, you can use any rifle you want and you can do so in July. What the CO would have been charging you with is unknown to me, that it probably why you were not charged as you were not doing anything wrong. There are municipal restrictions on target shooting in some areas, down in SW Ontario I know of one that says nothing larger than .243 but it is not a blanket statement across Ontario.