The only use for a penetrating lubricant for use with a weapon is the freeing up of frozen weapons. We recovered an Uzi in a case next to a stop sign in a very rural area. Seems that "someone" wanted to ditch the weapon, but have it found. Apparently is was exposed to a fair amount of rain and the poor seal on the plastic case allowed moisture infiltration. The bolt froze in the receiver and the contact points of the "egg crate" foam left surface rust patches. We used a good deal, 5 gallons of liquid WD-40 to soak the weapon and free the action. It loosened up after two days in the bucket. We then rinsed the weapon and used "Machinegunners" lube to displace the WD-40 and reassembled the weapon. All this to verify that most weapons lube is designed to stay where you put it and a penetrating lube migrates. Everybody here has a favorite, I like the moly based "Machinegunners lube from Sprinco via the web. Slick as can be and stays where you put it. Check out the stories on CLP concerning use in Iraq and it's tendency to attract sand. I've never used it and cannot personally comment on that aspect. Good luck and good shooting!