I don't think there is a "safety" issue with firing buckshot through it but if I understand correctly there are spread issues. Seems that the rifling makes the buckshot spread out VERY fast, or so I hear.

It's also worth noting that what you will generally find is that in a 20 ga a 3" loading of #2 buck is the best you will find. Not big enough shot unless it's a very close one.

That said might not be a bad thing to have should you end up trailing a deer. If he jumps a couple of barrels of #2 buck would be usefull.

Another thought is to contact these folks, http://www.dixieslugs.com/

They make a load for the 12 ga that has 3 very big balls and I understand they are working on the same for a 20 ga.