I know a couple of guys who've killed mtn lions with 22 magnum revolvers. They're no more bulletproof than deer. What makes you think that a 223 or 22-250 in a contender isn't sufficient for cougars.
My Grandad killed a mulie with his 38 special 4" M10 one year, turns out a 158 RN factory load will break a deer neck at 40 or so yards. Shoot sheit in the right place and it dies, that's how it works, how it's always worked.
