HA! Barrel blanks are not a problem - the problem comes when something finished looking hits the border office. Then the crap sometimes hits the fan, sometimes not.

Too changing the calibre of a registered firearm, 12 bore to .45 cal. might not sit well with whomeever is examining it - if it is indeed recognised.

Many of the rifles I registered, I registered having multiple calibres, etc, just because they either existed or I'd planned on adding them later. The registration card has no calibre on it, but running it into the computer system brings up the whole schmele, I'm told.

Of course, when the Senate gets finished rubber stamping the Tory's law, registration becomes moot and all is supposed to be destroyed - to the consternation of Quebec.

How that will effect customs, I've no idea.