Rifle weight is a personal preference. I prefer 8-9ish lbs. I find I shoot a rifle of that weight much better from field positions.
I would suggest everyone find their optimal body weight as well. Mine is around 210lbs. I'm a little over 6'1 and lift weights 5 times a week and perform cardiovascular training 5-6 days a week.
Military rucking studies have shown muscle strength and endurance matters more than cardiovascular training when rucking with heavy weight, which is why I have no issue carrying a bit more muscle mass.
I packed out three elk last year while carrying a 10lb rifle. I noticed the bone in rear qt, front qt, and neck meat on the heaviest load. I didn't notice the rifle.....
