Jesus, we should add "simplify the regs" to the list of requests the firearms community has of the government.
If the barrel has been SHORTENED after leaving the factory "by sawing, cutting or other alteration or modification" to less than 18"/457mm, that forces the firearm into the "prohibited weapon" class.
NOTE: The firearm is NOT forced into the "prohibited weapon" class (i) if it left the factory at the below-18"/457mm barrel length,
(ii) if it was refitted with a factory-made or even gunsmith-made barrel at the below-18"/457mm barrel length
UNLESS the barrel was at one time a longer factory-made barrel that was shortened "by sawing, cutting" etc.—in which case it falls back into the "prohibited weapon" class.
If the firearm ARRIVES at the "less than 26"/660mm in overall length" condition by "sawing, cutting" etc., then it is forced into the "prohibited weapon" class. If it left the factory at that too-short length, or arrived at that too-short length by the addition or substitution of factory-made or custom-made parts that are NOT SHORTENED FACTORY-MADE PARTS, the limit does NOT apply. It is unrestricted, UNLESS it is semi-automatic AND centrefire
CURRENT LAW CC s. 84(1) "restricted weapon" (b):
If the firearm ARRIVES at the "less than 26"/660mm" overall length by "folding, telescoping or otherwise" INSTEAD OF by "sawing, cutting" etc., it is forced into the "restricted weapon" class. If it left the factory at the too-short length, or arrived at the too-short length by the addition of substitution of factory-made or custom-made parts that are NOT SHORTENED FACTORY-MADE PARTS, the limit does NOT apply.
So no sawing or cutting.
All laws apply to CENTERFIRE ONLY!!!!. Rimfire all bets are off. use a 50 rnd drum mag all you want

lol