there is a section on the T&E in the US Army TC 3-22.240 (medium machine gun) and
TC 3-22.50 (Heavy machine gun). you can also try contacting your Infantry school and the US Infantry school (you might have an LNO there) to get copies of the machine gun theory classes. (The one I took at OBC was taught by an Allied SGM).
Unfortunately, must of my experience with the M2 was free gunning in the sandbox. The only recommendation I can make is to practice making range cards.