Calculate Speed From Arrow Drop


    

Follow steps :
  1. Shoot a group at a target (minimum 3 arrows) from 20m using your 20m sight mark (or pin), If the group is not small enough, repeat it few times or shoot more arrows until you will know where is exact center for the group
  2. Mark the center of the group (it should be the center of a target if you have set your 20m sight mark (or 20m pin) correctly)
  3. Move to 40m, still using 20m sight mark (or 20m pin), aim at the center of target again
    Shoot a group (minimum 3 arrows). If the group is not small enough, repeat it until you will be sure where is center of a group on 40m
  4. Mark the center of the group
  5. Measure the distance between the center of group on 20m and the center of group on 40m

    milimeters

    milimeters

    milimeters

    Calculate


    ... fps
    If the speed doesn't match real speed, only reason could be, that you did any mistake during measuring distances or identifying correct center of groups