Quote Originally Posted by zooma View Post
I believe this is called parrallex, and there is no adjustment for this on the Whitetail 1.5-5 x 20mm, so it looks like I need to find a sight more suited to the closer distance of 10 metres, or find one that can have it's parrallex adjusted for use at this relatvely short distance.
It's still possible to adjust the parallax free distance. 10m is close range, but it should be possible to significantly reduce the parallax error you are seeing, if not fully remove it.

Here's a link showing what is involved. It's one of those jobs that is easier to do than write an explanation of.