ok, here goes my 2 cents.i shoot recurve, no crossbow. same info will help. been shooting deer for 40 years. first, you have to practice.i climb on roof and practice if i hunt out of tree.i like to hunt on ground as i can move.PRACTICE. as for scoped horton etc .crossbows. set your bow so it shoots dead at 20 yards. use only the 20 YARD PIN OR CROSSHAIR.now, go up on roof or shed.set target at 20 yards and shoot.if deer is at 10 yards ,you have to shoot lower, use the 20 yard sight not ten. out to 30 yards, you aim little higher up deer..closer deer ,higher it shoots, farther away the lower it shoots.never shoot over 30 yards.you have to practice. if i can only give you 1 thing to remember. USE ONLY 20 YARD CROSSHAIR AND PRACTICE. i saw more deer wounded and missed by using those different yard crosshairs,like 10,20,30 ,40.sproulman says, DONT USE THEM, use 20 yard crosshair for all shots to 30 yards.also, learn your yardages. throw the range finders away. you can learn it.trust me, been doing it for long time.hope this helps.normally out to 20 yards you have toAIM lower ON DEER TO SCORE. HOW LOW? PRACTICE.