http://www.excaliburcrossbow.com/catalog/crossbow/the_vari-zone_crossbow_scope I can't see using an x-bow without something like this. If you don't have a chronograph, zero the x-bow at 20 yds. Put the target at 40 or 50 yds and keep turning the speed ring until you are hitting the aiming point. Always shoot from a bench type rest when sighting it in, it will take out most of the human variables. I use a rangefinder when hunting, either on the deer itself or on landmarks around the stand so I know the yardage. Trajectory is like a rainbow.
I use mechanical broadheads, they fly the same as my field points.
One thing - have a magic marker with you, and shoot ALL your arrows at the 40-50 yd target. Any arrow that doesn't fall within the group, re-shoot it. If it falls out of the group again, mark it and don't use it for hunting. All arrows won't fly the same due to how the fletching and nock is installed - something to do with the spine of the arrow I think.
