Quote Originally Posted by lensman57 View Post
How accurate it is depends on how accurate the value of the BC is that is allocated to pellets. I find the values in the library a bit over optimistic for long range shooting. For example a JSB exact 8.44 has a qouted BC of 0.022 but I find that in my S400 this value is more like 0.019 . The good news is that if you restrict your shooting to 45 yards the error is small . You also need to give an accurate scope height otherwise all bets for short range precision are off. Once correct values are used the results are very close to reality.

A.G
Our own Brian Samson said to me that the BC makes only a little different compared to scope height. Now he also told me that scope height isn't the center of the scope to the centre of the bore but the distance from the line of sight to the centre of the bore at the muzzle. You can figure this by setting the zero distance you want a then put a cover the objective of the scope with a small hole in the middle of it which will help it focus at the muzzle, then put a dot on a bit of paper aim at the dot with the muzzle as close to the paper as possible and fire. Then measure the distance from the dot to the pellet strike.
He also showed me a pic of the theory which I'm not sure where is now. After doing this with my huntsman I'm pretty sure it's 40mm accurate out to 75yrds (wind/power consistent and all the other factors considered).