RE: Elk & Antelope archery
A 40 pound bow will kill elk all day long.
The keys to effectively taking elk with low power set ups:
Make absolutely sure that your bow is perfectly tuned to maxamize the power your set up does have.
Use a very sharp two blade cut to tip broad head like a magnus stinger or steel force.
Limit your range to 20 yards or less. This in not as hard as you might think.
Do not take any shots that have the slightest possibility of missing the mark.
Limit yourself to broadside or slightly quartering away shots only. Never take a head on, quartering too, a shoulder blade shot, or a heavily quartering away shot.
Do these things and you will have no problem killing an elk.