arrow rise or drop

[nchunterkw]

Since the scope is mounted approx. 2" above the rail, the arrow has to initially rise. So if you use the 20 yd marker, at 10 yds the POI will be slightly high. At an arrow speed of 300fps it's about 1" high.

However, you'll find, with an arrow speed of 300fps, that at 5yds, the POI will be identical to the one at 20yds. An arrow at that speed crosses the line of sight at 5yds (going up), reaches the top of it's trajectory at approx. 12.5 yds and the POI is about 1.4" high and then crosses the line of sight again at 20 yds (coming down).

Hope that helps.

This is exactly right. All of our bows start the arrow at an upward angle. If you have the Hawke Ballistics App for your phone it shows this. The data for my current setup according to that is below.

Range (yds) , POI (in)
0 , -2
5 , -0.07
10 , 0.94
15 , 0.99
20 , 0.00
25 , -2.08
30 , -5.31

and so on.

[nchunterkw]

When shooting an arrow horizontal to the earth, the gravitational pull is on the whole length of the shaft causing it to be pulled to the earth sooner.

When shooting straight up or down, gravity can only pull on the end of the shaft which will cause no trajectory.

This is not correct. Gravity acts on the whole mass of the arrow at all times, pulling it in a direction perpendicular to the surface of the earth. If you actually shot "straight up" or "straight down" - meaning exactly perpendicular to the earth - gravity would still impose the same force on the arrow but it would be exactly in line with the direction of travel either adding to or subtracting from the arrow's speed.