I'm not sure about it's exact specs but I know you came to the right place for an answer. I do know it's a big gun, has a long range, and is designed to shoot things.
It is used to remove heads at a VERY long distance. Basically, you can hit a human with that thing at over a thousand yards anywhere on their body and the head (as well as the rest of the body) turns into tiny pieces....very effective against terrorist hiding behind walls at a thousand yards :)