[Dragline45]

I don't think they jumped with their rifles disassembled. They were jumping behind enemy lines, often while getting shot at. It wouldn't do you much good to jump into enemy territory and have to take the time to assemble your rifle while surrounded by the enemy in the open. Also not all WW2 paratroopers carried the M1. One thing I will add is that it was a common occurrence for those leg bags to get ripped off from the prop blast as they were jumping.