Originally Posted by Capt
Well, after some POI trials yesterday chairgun tells me 55 yards should be 43 clicks on my turret. It turns out it actually is 30 clicks. Power is quite constant :confused at 772 FPS, I can't believe chairgun can be that far out so its either my turret is faulty or I have POI shift as explained in the link below?
I do have an AJP riser rail, Big Nikko mk3, Barry Taylor side wheel, bubble level, Rowan top turret & pointer on the MPR. Could all this mass be causing this shift as the barrel isn't floating?
POI shift is only a term for a shift away from your previous settings, not some theoretical settings.
Chairgun can be that far out because most people don't measure the scope line of sight above the barrel at the muzzle, and there can be quite a difference between that and your scope line of sight at the breech. Also the Ballistic Coefficient used is also theoretical and can be different to reality.
You don't need a windless day for 10-55 trajectory, just 10-55. It's easier on a stiller day, but i've never done it on a still day or certainly waited for one. Just get the tape out and shoot paper from 10-55 and you're done.