Originally Posted by
stephen m weiss
Ah thanks so much! I had actually read both of those posts and most of the replies, but the definitions of 'lube purging' and 'consistency' were not clear enough for my mechanist head. Even now, I see no hypothesis for why the lube builds but then suddenly purges, so I will toss one out: the wave equation. The lube stuck to the barrel becomes effectively liquid during bullet passage but then cools rapidly and stays for the next bullet. As the deposition depth builds, so do the surface waves created ahead of the bullet. Eventually, the resonant point is approached and the wave breaks and all the wax becomes involved and pushed in a bow wave ahead of the bullet. Why is the shot always high??? Longer barrel time for the purging shot is my guess. It's difficult to tell with chrono data. I can see only that the nature of the exit of the bullet from the barrel is affected, with most of the old grease on the bottom of the barrel and deflecting the bullet at exit. Sounds sketchy but could be true.
This explanation begs the question, why didn't the packing scrape out the excess lube with every shot? I don't see much in the way of purge flyers when using fillers behind the bullets. The circa revolutionary war cannonry guide I read somewhere said that was one of the functions of the hay put ahead and behind every shot. Could it be that the popular use of Dacron has so little volume and stiffness that it rides right over the lube? I dont see the lube buildup problems even after 40 shots or more using Lee Alox and grits or toilet paper filler. Dry barrel...I motor oil lube it for fear of rust. I do see 5-15 chunks of grits in the barrel when looking down it, all within 6 inches of the chamber end. I brush that out before re-oiling so it wont get stuck in the oil.
Just stirring the lube, pardon my curiosity and critique.. shoot me down if I am all wet..with lube buildup... :)