Originally Posted by tugg
I have found this to be true , when using a Lightstream I had.
I used to make sure the outer part of the cross hairs intersect at the centre of the arc of the eyebell but to do this the centre was always offset to the left slightly .if that makes sense
To be honest, when I found this out I felt a bit stupid because when you think about it, it's obvious really.
A while ago when I was writing those HFT Ninja guides I needed to have some photo's taken through a scope so I made a little jig to rig up a camera mounted behind a scope (not on a gun).
I wanted to perfectly line up the crosshairs with a part of the kill and I didn't want it to be jogged when the shutter went off, so I bolted everything down and clamped it all in a workmate bench.
It got to be a bit tedious positioning the bench perfectly so I had the bright idea of just adjusting the turret to get the crosshairs exactly where I wanted them to be in the photo, but what I found was that when I adjusted the turrets, the edge of the sight picture became blacked out. The camera was clamped in and set at the optimal eye relief distance and everything was bolted down so it couldn't move.
That's when I had the Doh!! moment and realised that if I moved the turrets then the light coming out of the ocular lens wouldn't be coming out directly behind the scope it would come out at an angle.
Now if you don't match your head position to the angle the light is coming out, then you'll get parallax error.
How many times have you seen in a forum thread people boasting that they don't need a scope enhancer because they always get a consistent head position. Well that consistent head position you get, could end up giving you a consistent parallax error and lead you to come to the wrong conclusion that it's your mounts giving your crossover.
Moral of that story - use adjustables and optically centre your scope.
Anyhoo.. that's a bit off topic for the original post - my advice would be to listen to Rammy's advice and convince yourself he's right by getting a 20mm practice target and practice shooting it from every half yard from 8 to 25.
Once you've got the confidence that you're going to hit it, the close one's become a welcome 'gimme' on a course.