re: Adrenaline
One must factor in not just the few seconds a weapon is actually being used in combat, but the long hours of practice required to become truly proficient and at home with it. To be really effective in a time of high stress, I would imagine one should have spent a great deal of time getting familiar with the piece in a variety of conditions. I still cannot fire a 44 Magnum without tensing up and flinching. I probably subconsciously close my eyes in anticipation of the report.