User blog comment:Leolab/Retroactive Unfair Battle Enforcement/@comment-24180428-20131109055815/@comment-5559147-20131110040723

The M2 is often considered a sub class of the M1, an M1 variant if you will and the M1 used by Indy on screen in Crystal Skull was the select fire variant with a 30 round mag. So while the picture used in the match was an WW2 era M1, I assumed it was a mistake on the authors part while looking for pictures.