We tested many silver and black scopes all 50 mag all various versions of the same scope on loan from the factory. The control scope had plastic inserts in the mounts which in turn topped a rail . Other scopes in black and silver in all metal mounts direct to dovetail.Over a 18 month period we tried the mounts hardly tightened or scope just taped into mounts all scopes and set ups appeared to shift at around 9.When the temp reached 8 it was like a switch and under ranged from 35 y to 55y.
However and this is the next problem the amount of under ranging did seem to be related on rare occasions to light conditions, this may also be linked to the day you choose to mark up your side wheel. Next we covered the control scope in 2 layers of thermal sock , just the wheel and the glass uncovered. The scope was left outside before and after covering and also tried covered from car.Did seem to work but switch had gone and also under ranging was only delayed but could also be poor light. Tried with sun shade to top turret covered looked daft even more so when Chloe stuck 2 googely eyes on and did not work.
Next took black and silver scopes into a poly tunnel got up to 30 temp wise both ranged 55y spot on.Same day placed outside in full sun different light as poly tunnel is tinted grey, both scopes over ranged 55y by a fraction. .
Chloe and Alan