Maybe someone can explain it so it makes sense to me, but unless the neck is fully opened before the bullet starts moving, and unless the lube is eroded by the passing gas column to carry some minuscule amount out ahead of the bullet before it is in the leade I have a hard time seeing any significant amount going ahead of the bullet from which it came. Why don't we see lube onthe nose of the bullets we recover? Where I get tied up is the idea that all this happens in a series of repeatable events. It's the same issue I have with the idea of lube "melting" from heat from the gasses. It takes time, even under 40KPSI, for heat to transfer, start the melt and then start to spray anywhere. Meanwhile the neck is opening and the bullet starting to move. We're talking micro-seconds. That's the time/pressure/distance thing I alluded to. Isn't that pressure pushing the lube into the lube groove or any other space too? Shouldn't we be finding bullets with a gap between the GC and bottom part of the bullet full of lube then? The pressure rising in the cartridge isn't pushing forward, it's pushing everywhere until the bullet starts moving and then the pressure moves to fill the space. And if the bullet is one of those Loverins with, say, 8 lube grooves but only the bottom 2 filled, why don't we see evidence of lube in the upper grooves after firing? I'm back to, "I dunno." I don't have the education to put in terms that might sound more scientific.
Unc Jimbo- Yeah, the air in the barrel along with anything ahead of the bullet, assuming a well sealed bore, is going to shoot out ahead of the bullet under compression. Any residual oil, lube, powder ash, dust, etc is going to be pushed out.