Wondered for years all the so called scopes that apparently moved with temp, slated and flogged on, most of the time its the user.
Its not necessarily bright light can be dull in winter or peak of summer. Even seen +6 yards registered, 5 mins later bang on with no apparent change to the light above, certainly no temp. The change is your eyes.
Stands to reason as materials expand and contract, theres going to be some movement but the only way to determine is in controlled conditions and constant lighting by at least three different testers climatised in the test area.
One instance dont cut it.
Black absorbs heat but slower to dissipate.
Thought Robs white one was a Tasco variant.
300mm, i couldnt get within +/- 3 yards on a good day with a hand chosen Mark2 Niko (Feb 2004).