Since I do not have access to a chronograph I attempted to check my speed using the ol' 20 yd - 40 yd same pin group method. Shot 3 arrows into a tight group at 20 yds and backed up to 40 yds and using the same pin aiming at the same spot shot another 3 arrow group. Another tight group. Great…measure the distance between the center of the two groups. Wow... 9" difference between them. By the calculators i've seen online my bow off the charts fast. It can't be right. What am i missing???