Originally Posted by
Bigslug
I said it about a bazillion pages ago - you REALLY need to track down a high-speed camera.
I tend to think that once lube gets blown past a boolit, it's going to STAY ahead of that boolit, and probably in a vaporized state - the blowby gasses are moving faster than the boolit can at that point, and even if the boolit obturates to seal the bore afterwards, the boolit is providing a push to the column of air inside the barrel ahead of it, probably carrying the vaporized lube.
I'm not sure how to conduct THIS test, or what specifically to test FOR, but it might be worth applying high speed video to different barrel lengths to get a better idea of what the lube is doing where. I tend to think the only valid way would be to progressively chop back a sacrificial barrel so it would be known for certain that length would be the only changing variable. I think by observing the gas plumes, we'd stand to learn a lot about the sealing effects of both lube, obturation, and the mystery of gas checks. Hell, we'd probably learn a lot about how different powders work when applied to diffferent BHNs.