[{HVY-E}Jinxx]

Also...I think all of teh 50's were M-2 model and not M-3

M2 is the ground variant like we use on vehicles or in a tripod.
M3 is the electrically actuated variant. Typically used in remote fire systems, a/c etc. There are different versions of this depending on application.

S!

Jinxx I thought teh M2 version was used during WW2 and teh M3 was developed as an improvement after teh war. It seems i remember teh m3 having a higher rate of fire than teh M2.

Both were used during WWII with the M2 being developed back in 1918 and the M3 during WWII. The M3 does have a higher rate of fire. (appx 1200rpm vs. appx 700-900 for the M2 if the head space and timing is just right).
The actual designation for the models used on A/C were AN-M2 and AN-M3. They are remotely fired, electrically operated via a solenoid instead of a butterfly trigger, (Same thing we use in our Strykers for my unit).

The .50 is generically called M2 or Ma Duce by most everyone, but there are 3 or 4 variants.
My unit even had an M2 from WWII as none have been made for quite some time and all that are in service are constantly being refurbished.