Any god that designed GURPS would by necessarily be malevolent. 
~Umi

~Umi
I think if you want to be very hardcore and invested in firearms specifically, Phoenix Command is kind of like the old holy grail. But it's really hard to get those books. I had to buy them used on the internet...Drivethru RPG doesn't even have it.
Even then I felt there were at least some tweaks that needed to be done honestly to portray evolving tactics. Like in Phoenix command it wasn't possible to shoot while walking in a professional manner; you were considered to be firing from an unready position. I know that older or more traditional curriculums didn't necessarily cover that. But today shooting while walking is part of the general curriculum. You're still not accurate at range but if you do it right you're a lot more accurate at closer ranges than if you're firing from the hip or an "unready position". Someone who is good at it can still hit a plate at 30 to 50 feet like a magician, ding ding ding with each step.
Basically it's too bad that that RPG isn't widely available, since if there were a dedicated team of rules enthusiasts I think that system would really benefit from an overhaul to represent modern CQB tactics.
I'm in awe of that system though for all the stuff they thought of in the context of the time that was written which was before the day of realistic video games. All the stuff like changing posture taking time, firing from the hip versus firing in posture, that was all implemented in Phoenix Command. Even the to-hit rolls were divided into a windage and elevation calculation section to determine where the round hit.
Also, to go with thread title: http://www.youtube.com/watch?v=CEFrvBSk5kw