Hey guys my 1st post on here (long time lurker) and thought I would throw in my 2 cents. I've killed 3 bulls archery with light arrow set ups. 2 with easton flatline and 85grain wac-ems, from ranges of 3, 25 and 55yds.
Arrows kill by cutting and not kinetic energy. So use what arrows your comfortable with and practice, practice, practice. Shot placement and sharp broadheads are what is important. I don't know how many people have told me you can't kill elk with 85 grain broadheads.