Thread: How close is your trajectory profile?

We had trouble with a long range rigs impact when getting out past 400 yards. We looked at all possible explanations as to what may be causing the inconsistency between the ballistic readings and the actual impact point.
We then changed to a different crony and discovered 170 fps difference in the velocity readings which made a huge difference to the dialling and subsequent impact point.
Also wonder what distance is the optimal distance from the muzzle as the bullet will take a bit to reach max speed. Chronograph instructions seem to be quite flexible in directions about the distance from the muzzle.
Another interesting observation when firing factory ammo through 2 different 300wm's was the large variation in velocity between the barrel lengths. One rifle with a 24 inch barrel was achieving velocity of 3225 fps with 150 grain projectiles and the other with a 27.5 inch barrel was getting up to 3400 fps.