it USED to be that way.
You could re-manufacture a barrel as long as it was by a "certified" barrel maker, whatever that means...
Now, the barrel can only be made to that exact length, you cant cut it down SHORTER than 18.5". So if you had a 26" barrel you wanted to be 22" or something, that's perfectly fine, but if you have a 16" restricted barrel you want to shorten to 10" or 8", then thats not cool...
It has to be a "brand new" barrel made to the length you want. All it does is cost guys like me and you more cash (100-ish to cut, crown and thread a USC barrel to 8" from 16?) versus the cost of a brand new barrel blank, then the machine work to profile it all the way, then the chamber reamers to cut and finish the chamber, THEN crown and thread (or machine flange into)... and it doesn't do one darned thing to stop criminals from chopping their barrels down.... }:-(
Another great "change of heart" from the RCMP within the past few years.