Yes, we found that once the sun is in the treeline, it wouldn't work. Even a few shadows interfered, and our best results were when we took the plastic canopy off.

Another interesting thing: Two weeks ago when we first tried it, my mate tested some 6.5x55 loads. This time, the same load tested almost 200fps faster. I think last time was maybe five or six degrees cooler. Does temperature make that much difference, or is something whacky somewhere? Unfortunately, I didn't bring the .416 Rigby out again to try yesterday, but when we used it that first time, its reading was a very satisfying 2350fps. Are some cartridges affected more by warmth?

For me, it is purely interesting to find-out. I very much doubt I will change anything on my .450/.400, as with solids or Hydros, it shoots through buffalo and bulls. And having used the .300H&H happily, I doubt I will pursue 3000fps with it, either.