Ok, out of everything to talk about this is going to seem like a silly question, but why does the guy tap his mag on his helmet before slamming it into his rifle? I've seen that before in films, but it was in WWI where they tried to fool the enemy into thinking they needed to reload.
Is that just a superstitious thing or is there a rationale behind it?
I was actually going to ask the exact same thing. I always assumed it was to check if the mag was full without taking your eyes off the field.