Went thru boot camp at Parris Island with the M-1, you could look down tables sitting in the mess hall and see the black thumbnails.
I had a couple of them tell me the worst part started the day after when it was purple and swollen and they still had to push those clips in.
I’ll bet most guys only had it happen once! Can you imagine if you did it twice in a row? I am certain if I did, I would violate a number of range rules in short order, not to mention cuss up a string that would hurt the ears of the most plain and fancy of cussers!
Not a Marine, but had the M1’s baby brother, the mini 14 bite me hard during factory armorers school. The factory rep. told me it was a self correcting mistake. You never did it again. To this day My left thumbnail is twice as thick as my right, and kind of uneven.
CC