I used to mix up a combination of bees wax shortenitn and vaseline like Mr. Eames does. There was some stuff called pistol patch, from blue and gray products, that came in a plastic squeeze tube like tub caulking, and was about the same consistency. When I could no longer find the stuff, I switched to tubs of bulk white high temperature lithium grease from the auto supply store. One pound will last a couple years. I put the grease in a metal icing press to use at the range.
When I first started, old timers used fibered water pump grease. It was pretty stiff as grease goes. Don't know if it is still available.