Heard an archery equipment reseler say that there would not be enough kenetic energy left in an arrow at 80 yrds to kill an ELK. Shooting a 400 grain arrow at 288 ft. per. sec. which is 73.7 ft. lbs. atthe chronograph. Is there a way to figure what it would be at 80 yrds. Does anybody have any input on this. I don't have an 80 yrd. pin, but I have a 70 yrd. pin. I held off shooting at a nice Elk at 80 yrds two years ago because I only had a 60 yrd. pin.

Heading to Co. the first week of Sept.