that wouldn't me a mark 2 in your avatar would it?
(so does this mean I wont be seeing a few of those boxes on my doorstep?)
I don't know what it is but I can tell you that its a lot bigger than my little .22 and sure gave a much bigger kick.
Its not mine but when I go to the range, people tend to want me to try theirs out to see what my limit is. Which is not much LOL