Killing a mountain lion, huh? I wonder if a mountain lion got a jump on you if you could take him with a tucked away pistola?
I propose that preventing an encounter with a mountain lion with something like bells and/or flashing lights is a better solution to that problem. None the less...
I guess if I was going to try and kill one I'd want high capacity, and train with a nine mil like a beretta, Sig, or other. Polymer frames are lighter weight and might be appropriate for a man-pack exercise like a bike ride or hike in the mountains.
On the other hand an m1911 in 45 while holding a max of nine rounds (compared to the 18 or more for the nines), will probably be effective even if your accuracy is a little off.
Riding a bike, legally packing with a CCW, I'd probably opt for the nine. I don't know enough about 40, .380 or some of the other semi-auto handgun calibers. I know, respect, and am effective with the nine. I would definately not hold a revolver of any sort with a revolver strapped to me.
I've got to admit though...Revolvers Rule. Big, heavy, accurate, strong, easily maintained, simply operated, extremely reliable. Brilliantly effective. You can kill elephants with that freaking 500 magnum or whatever that s&w is hawking these days. A 357 will stop just about anything most of us will ever encounter.
You ask a profound question friend. I wish you a steadfast mind in your decision making.
Be wise and be safe.
Maybe that's your answer. A revolver in the paniers on your rig, and a nine strapped to the small of your back.
Only thing missing is a shot gun
That's what I would want handy should I encounter a mountain lion bent on my demise.
out,
-bear