I have a 6.5x 20x 50mm Whitetail Classic, imported from USA. [At the time I was told by a Guy in Simmonds technical that they were really Whitetail Expeditions and optically excellent value for money but had the wrong finish for that range [due to an ordering cock-up]and hence were sold off within the cheaper Classic range.

Anyway shooting from a very warm dinning room last week into a coldish garden seemed to give a wierd effect, a sort of shimmering as the target went in and out of focus. A bit like the effect of heat-haze on sand ot tarmac.
I put the gun on our custom-made gun bench [20mmx20mm solid stainless steel] so it was totally rigid and I still got the same effect.

I waited till the wife came home and asked her opinion. She said it was a bit hazy, and also saw the same effect so I looked again and was suprised to find that it was now fading in and out of focus much less than before. By now with the door open the room was a bit cooler.
Is this normal? or are there gases in the scope, and if so have they leaked to produce this effect?
Any views on this much appreciated as i obviously can't ask the US supplier for there opinion.