I feel totally secure with my Win. Trapper 30/30 ...
Certainly beats any .223, IMHO.
But then, I favor power over capacity (living in the country makes over-penetration less important). I figure if I haven't stopped the threat with a few rifle shots, I need to be evacuting the premisis. And I'm simply not going to beat the brush searching for high-cap magazines, either.
I'm not a combat instructor or ballistics expert, so this is just my opinion, but I don't think any rifle caliber (.223) that is incapable of taking deer should be relied upon for self-defense.
That said, around here magnum pistol-caliber carbines like the .44 mag and even the .30 Carbine with softpoints have a deer-taking reputation, so 30/30 as well should be excellent.
I know, somebody is bound to say, "But DEER aren't PEOPLE, so your comparison is invalid."
Well, maybe, but to my mind they are way more like people than gelatin is. It's also hard for me to bet my life on some magazine article on One Shot Stops.
My theory is "I knows killin' power when I sees it."
That aside, so long as you practice with your lever action, what could go wrong?
Hope this helps.