best defensive caliber and why?

[Skinny Shooter]

I prefer a 1911, Springfield XD45 and the revolver I mention below.

GOB, I like the lever 30-30 idea.
Now this is not a scientific conclusion and is based on one event.
I winged a groundhog with my 22-250 at distance.
At that time I was carrying a S&W 686-plus snubbie loaded with 38's for close-in shots along fencerows.
Found the hog in its hole.
I put several shots into it and it came out of the hole after me.
One shot from the 22-250 in its face put it down.
From then on I only carry 357mag in the gun.
Of course a person will react differently but it set me to thinking...