I'm not sure if he ACTUALLY used one, but that is the same one in the movie. It is highly likely he did use one, as the military used those on M24s and Kyle used a 300 win mag M24 during some of his deployment. He also used a McMillan Tac-338 which had the MIRS as an option, (not sure how Kyle had his set up) that's the rifle he made his infamous 2000+ yard shot to take out an enemy sniper.
hope that was helpful
P.S. If you're looking to actually use this as a forward rail, make sure you use the larger 8-40 screws cause this is supposedly pretty stressful to the scope base screws. (note that I've never used one.)
I personally bought a Badger EFR (not yet installed) and it seems like a better system, but it has to be bedded. I'm also not sure if you can get this in Australia.
Yeah mate that's why I said it was the one used in the movie. Yeah I've got 2 MIRS rails as well as a MARS rail sitting in my shed sent from the US! I've got one going on my 300wm and was going to get rid of the other MIRS..just tossing up whether to put the MARS on my 308 or not.