I don't know. .223 just doesn't have the same oomph power that .45 brings to the table. Especially when you're going after coyotes in bear country, there's nothing like having that reliable knockdown punch that .45 brings to the table.
And let's not even get into .45 having a much more dominant trajectory than those annoyingly flat-shooting .223 rounds. Same principle as the Javelin missile really, and how effective it is against tanks. Imo, top down kills are something that's really only made possible by using Javelin missiles and .45. And no one is going after coyotes with Javelin missiles (obviously).