this is off of every firearms registration certificate.
"Firearms owners must report to the Registrar of Firearms, within 30 days:
-any modification to the firearm that affects its classification (non-restricted, restricted, prohibited);
-any modification that results in the firearm ceasing to be a firearm;
-any modification to the type, action, calibre or gauge of the firearm; and
-any modification to an altered automatic firearm."
barrel length does fit in on certain conditions but not on this one.