Here in Canada, customizing a rifle with a 16 inch barrel might make your gun a restricted firearm is my understanding.
You can buy a rifle like a Ruger or Remington, etc. with the manufacturer's 16 inch barrel but you cannot replace an 18 inch barrel (the minimum) with a barrel under 18 inches or it will become a restricted firearm.
Guys here in Canada building 12 inch barreled rifles from a stock Ruger 10/22 are likely required to register them as restricted firearms.
Ok simple way to look at it
AR 15 restricted no matter what
AK 47 prohibit no matter what.
Tommy Gun Prohibit mp5 same thing no matter what
Now a Center fire Semi auto has to meet 2 things to be non restricted. 18.5 inch barrel or longer and must be longer then 26 inches
Now a Rimfire semi auto has to meet only 1 thing 26 inches long
No barrel can be shorter then 4.14 inches or it's also a prohibit firearms
Handguns can't be reclassified no matter what barrel is put on them They're restricted or prohibit only
Rifles can be Nonrestricted, restricted, or prohibited.
All pumps, levers, bolt, break action, and muzzle loaders only have to be 26 inches to be non restricted.
It’s really simple to understand really.
Now you can convert a firearm from non restricted to restricted by changeing the parts and making it fall into the catagory I've done it both ways. I've had to change a frame only firearm into a firearm (10/22) was converted into a non restricted 10/22 with a 10.5 inch barrel but the stock made it 32 inches well over 26. If you want to go shorter and make a rifle restricted you can do it with an aftermarket barrel and then phone the cfo and they just change it over the phone or you have to have it varified by someone who can say it's this or that class of firearm. To do non restricted to restricted they will do it over the phone the other way around you need a gunsmith or have to take it to them its a pain in the rear sometimes if you do it your self.
