Worried? I'm really excited at the possibility of an ammo shortage.
Not just because I plan to flip ammo if the market goes bone dry, but because it means hordes and hordes of Americans are getting guns which personally, I think is a good thing.
Furthermore, I think it will really help a lot of shooters up in Canada develop a sense of discipline about shooting. I don't like the hardcore, military "count every round" principle that makes shooting not-fun, but I do think it's foolish and reckless to just go out and blow off a few hundred rounds willynilly for the sake of blowing off a few hundred rounds. If the price of ammo doubles, I think a lot more shooters will take shooting quite a bit more seriously than they do now and that can only be a good thing for the shooting community.
Personally, when I shoot, I like to make every round count towards a specific purpose - whether it's improving my personal skill and technique, getting my equipment in order, or testing out a new load. I prefer taking a disciplined approach to shooting, and that includes being disciplined with my ammo consumption AND production.