Jon will be along shortly connor to give reasons why i am sure . but i can only think that it possibly is the brighness of the immage that is making it difficult to range with and not the heat . the scope it's self cos of the silver finnish does not heat up as much as my black stock . today at 70 deg it felt cool . when i last used it at i think in the 80s . the rifle was difficult to touch it was so hot . the scope just felt warm . and was two and a half yards short . today , right on each line . andras has been testing the MK11 i believe . i wonder if he will come up and give his views .??? HOLLY
PS the difference seems to be the diffuser . but of course it could be the diffuser and old eyes .