high temp lithium wheel bearing grease. it stays where you put it, it doesn't burn off, and it doesn't migrate like oil. additionally it makes for easy clean up, because all teh carbon sticks to the grease, wipe it down and relube and you are good to go. I have been using the above on three deployments in the sand box, 8 training courses, both handgun and carbine, as well as every training session at the range that i do. Approx 30,000rds a year. I use it on ar,ak, handguns, shotgun, everything that needs lube.
it is like $3 a 1lb can, and that will pretty much last you a life time.