I own both a 243 an a 308. Took me a while to find what I wanted out of the 243 for deer hunting but once I did I rarely take the 308 out to hunt with. I hand load a 85gr hpbt game king bullet for the 243 and it has always did the job even on the bigger UP Michigan bucks. If the choice came down to only being allowed one I would again go back to the 308 works great with a hand loaded 168gr hpbt game king bullet. I don't believe if you can shoot half way decent you need a chunk of lead the size of a small pick up truck.
Al