In Colorado the minimum you can hunt with is a caliber the produces 400lbs at the muzzle and bullet weight of 45grs. That pretty much eliminates 22lr and 22mags. And for those that value the longevity of a good lion hound would not let someone shoot one with either of those rounds.

No futher than a person is going to actually shoot a mt lion bayed or treed a medium pistol or lever gun is all you would actually need to pack around. I would suggest a 357mag or above.

Mt. lions for the most part don't appear to be very tough when they are shot. But if a wounded cat falls into a pack of hounds, they can really tear up some dogs before the cat is put down.With anything else a good shot makes all the difference. And there's no pressure at the time of the shot because the animal is not going anywhere. I've only seen one instance where the shot was taken at over 50yds because of terrian. So most shots will take place within 20yds of the cat.

Have fun hunting your cat and the 270 win would be okay to hunt with but not actually needed on this type of hunt. Drag out that 30-30 that is doing nothing but collecting dust and give it a job.