Originally Posted by Strokebloke
Sounds like 30yds is the way to go. I'll stick with that. Thanks.
Q : Does the POI change if you shoot on different magnifications ? If I zero on say 20 mag, then shoot a close target on 10 mag will I have to make allowance for the reduction in magnification ?
It just happens to be that the max height of the trajectory is around 27-29 yds hence zero at 30 is just something that makes checking before a shoot fairly easy. I think most will say you shouldn't change your clicks shooting at a 'stranger' course but if your scope says it is 35yds and you normally add 2 clicks but find it is going high or low by a couple of clicks then when shooting the course you can add or subtract a couple of clicks so it all makes sense for that session. (There are all sorts of reasons why pellets can go high or low in cold or hot conditions). Then you go home, ponder, kick the tires and usually find it shoots fine on another day. However a lot of 'shift' comes from the position and hold which may not be as easy on a hilly course when you are used to a flat one for example.
POI is ideally the same on every mag setting, you can pay a heck of a lot for a scope that guarantees it is but reality is that you need to do the experiment for your scope. You can clamp the setup on a bench/workmate and focus on some tiny object at the back of your garden and gently zoom back and forward, the crosshairs should stay on the same point. If there is a reproducible shift you can either send it back or live with it and always shoot at one mag or away from the problem e.g. I have a 20-50 Leup which moves POI at 20x, I always turn it up from 20x to a bit higher and it is fine. I could send it off to Leupold for a service but then they may very well remove the Premier Reticle booster and spoil my fun :-)
As they say - it takes quite a long time to get to know your scope but competing on different courses is a great way to find out you don't quite have it all sorted when you thought you did :-)