All I'll say on that note is that the feed cover of the M60 makes a relatively comfortable pillow on those long, cold night ambushes.
I will add though that I have been so utterly exhausted while on sentry that I was halucinating. Saw vehicles, houses, trees, elephants and more moving about in front of me, but not one single enemy infantryman...
Good thing the expected attack didn't come until about an hour after I was relieved.