Here we go agreeing to disagree again. IMHO I did not find Full Metal Jacket to be a Vietnam film in tone at all. Yes, the Marine Corps boot camp was vintage and R. Lee was great, but the 'in country' plot played like the standard WW2 film. I think Stanley Kubrick wrote the screenplay in this way because he was such a hermit that he did not know how to portray the Vietnam experience.
I could be wrong but I believe most, if not all Nam vets would say Stanley's opus was only one-quarter to one-eighth jacketed...
I found "Full Metal Jacket" to be more surrealistic in tone, then any of the other VietNam era war flicks. "Apocolypse Now" blended realism with surrealism and told a good story, but not a new story. The "Bridge On the River Kwai" touched many of the same bases, 20 years earlier.
>>> ... Full Metal Jacket ... but the 'in country' plot played like the standard WW2 film.
Oh really. I'll bet you found the arrogance of Oliver Stone's "Platton" more to your liking and Kubrick's "Paths of Glory" also out of touch with reality. So be it.