From a previous Superintendant of Registration (post bill C68) the breach plug and perhaps the barrel of a percussion is the receiver.
Beyond what he said, some guns such as Wesson rifles and the small "boot" pistols do have true frames or receivers so that the barrels on them are immaterial. As Nessy said, in the absence of a breach plug, a barrel is just a barrel and just a spare part and in fact requires a breach plug and in some cases a drum or vent liner to define whether it is flint or percussion
cheers mooncoon
That is just the opinion of a bureaucrat.
Remove the breech plug from the barrel and it is just a tube.
The breach plug or the wooden stock may be considered the receiver.
Just another reason why muzzle loading firearms should be exempt from licensing, registration, and any controls at all.


















































