RE: 223 or 243
If you wouldn't have thrown deer in there I would have said stick with what you have or bump up to a 22-250. But once you bring large game into the equation then the .243 is the perfect round in my opinion.
I did the exact same thing as you. I live in lower Michigan where you can't deer hunt with a centerfire. I mainly wanted a high powered rifle to do some woodchuck hunting with, maybe a coyote or two. However there is always the off chance I will go up north and hunt someday and centerfires are legal there. So rather than getting a 22-250 I went with the .243 instead.
Paul