I was in SF for over 20 years, I was a 18B and a 18B instructor. When I went through the course in 1987 this was our final hands-on test for light weapons:
FULLY (20+ parts) disassembled 1911A1
FULLY (lots MO parts) disasembled M3A1 SMG
FULLY (yet even MO parts) disassembled M1 garand (yes, the trigger group too)
FULLY (can I get an amen) disassembled M1919A6 machine gun
So, you go into the classroom, having no idea what to expect (I think we trained on 60 or so different weapons) and on your table is the above- all piled up in a hideous pile of fuck. This was known as the pile test. I want to say we had 20 minutes to put all this shit together correctly, and that included headspace & timing on the 1919A6. To get a go you had to get 3 out of 4. The reason I passed the first time is I didn't even try to get the 1919A6 together- I just made dam sure the other 3 were right. This test was stupid then, and its still stupid, and years later when I was an instructor there it had been eliminated. Instead individual weapons (that the student might actually see/use one day overseas)were disassembled and assembled, and more training was given on troubleshooting common problems with specific weapons and having a real understanding for how they worked. Things that need to be worked on for speed are things like crew drills for machineguns (changing barrells, tripod mounting, etc.) clearing malfunctions, reloading, and the like. Oh- and delivering effective fire, since that's what they are built for. I'm reasonably sure that the chances of coming upon a pile of fuck in a gunfight and the feasability of quickly assembling said pile of fuck into several functioning weapons and ultimately putting them into action (presumably with the required ammunition, mags, tripods, etc. that the fuck-pile maker conveniently left) is more than remote. i hope this war story (even though there wasn't a war at the time) helped you. Or made you laugh. Or whatever.