O., I have been fortunate enough to have over 2000 rounds under Nikon's M-223 2.5-10 Laser IRT BDC 600 Scope. I was doign some testing/QC last June down here in Tx. 105 deg. in the shade. 1000 rounds of 5.56 and 1000 rounds of 7.62. I managed to get the barrel of the 7.62 so hot I melted part of my front rest to the barrel. This Range finding scope with BDC reticle functioned flawlessly. I was afraid about the excessive heat but no issues. I ranged multiple targets for 8 hours of shooting and all went perfectly. Panning allowed the displayed distance to change and the BDC Reticle lets you instantly utilize correct circle for dead on impact. The only bad part was that I had to send this scope back when I was through and didn't get to keep it! I showed this scope to hundred's of guys at Shot Show last Jan. and everyone wanted it! They can be hard to find so if you come across one better to get it then wait, just a suggestion.
I also want to add that when I did all this shooting, DPMS loaned me 2 rifles and both functioned perfectly. Not even one misfire in either Oracle.