mofire, congrats on your elk. but you pretty much answered my question. 65 yds is a heck of a shot and yet you still got a pass thru. If you can continue to shoot 70 lbs then be my guest. I have shot 80 lb when I was younger. But with today's faster more efficient bows you can probably reach the same kenetic energy with 60 lbs as you would with a 70 lb bow 15 yrs ago.
And after poking that big lug of a bison at 27 yds, I would almost guarantee a pass thru on an elk at twice that range.