The biggest problem and complaint from what I have seen is the rangefinder tells a archer to aim at a certain yardage, they do and the rangefiinder is wrong they are either shooting high or low. To know the exact hold over or hold under when shooting uphill or down hill requires one to know and calculate the exact ballistics/trajectory of the object in flight. This can be done if one could put in exact numbers, not just a gereral settings for a certain group. To know the trajectory of a arrow, you would need to know the speed starting out and in flight, weight of the arrow, and angle of the shot. If you could plug in these numbers then yes it would be accurate but instead on the Leupold Rangfinders you have to select three differnt bow groups. Below I took this right from leupolds web site. As you can see it gives you three different bow groups to select from. I cantell you one thing, I can have two different bows set up with different arrows weghtsand both would fit into group, but yet they would shoot totaly different and one could be hitting high while the other was hitting low. But because the rangefinder groups them together the reading would be the same for both. Example, I could have my older Martin Fury set at80 pounds, shooting heavy 2219's (615 grain arrows)fletched with 4" quickspins (they slow the arrow down and drop more than normal fletching) but yet starting out the speed would be in the 260's but it slows down fast and the arrows have a big time rainbow trajectory. Then on the other hand I could be shooting my Mathews Switchback set at 70 pounds, shooting 450 grain gold tips, and fletched with 2" blazers that don't slow the arrow down much. Both bows would be in the same group numberc on the rangefinder but yet the drop between the two set up is very different.

FUNCTION 14: BOW BALLISTIC GROUP

This mode, when activated, works with TBR to provide

the correct ballistic range for arrows. To select, be

sure that TBR is turned off (follow instructions In

Function 13), then select BOW by pressing Set or Power

on RX-II. The range that displays will correspond to the

target. It incorporates three different groups (Group A, B, or C) depending on

the particular arrow drop. You must choose one of the three groups, based

on your bow and arrow selection. Only one group can be selected at a time.

Selecting a new group deactivates all other groups. Most importantly, using

TBR effectively means Practice, Practice, Practice. Anytime you handle a firearm

or bow, you are ultimately responsible for where your projectile ends up.

BOW GROUP DATA

Bow

Group

Initial Arrow Velocity

(feet per second)

Drop from 20 yard pin

at 40 yards (inches) Typical Bow Description

A) Less than 215 f/s with 30" or more drop at 40 yards. Older bows shooting aluminum arrows and newer bows set at draw weights below 50 lb

B) 215 f/s to 250 f/s with a20" to 30"drop at 40 yards.Quality, newer bows shooting carbon arrows at 50-65 lb draw weight

C) 250 f/sor more Less than 20" drop at 40 yards.Fast bows with draw weights in excess of 65 lb