An artist friend (the fellow who painted "The Wall", the Viet Nam Memorial in Wash.DC) sent me a pint of pure pre-ban sperm oil, and I've used it in the locks and triggers of my flintlocks, but in all honesty I'm not sure that it is any better than the Ballistol I've used for years. In a cold climate it may be better, I don't know, but down here in Florida I can't tell any difference.
I've not tried it as a patch lube simply because I have excellent results with either bear oil or deer tallow for this. If I'm shooting chunkgun competition I use a patch lube of 7 parts water with 1 part water soluable machine shop oil allowing the patch to dry out before using. This produces outstanding consistancy in patch lube. For general hunting I'll use a mix of 25% beeswax and 75% bear oil which works well in our hot climate.
Cushion wads used in my double barrel flintlock and fowling pieces are rolled in this beeswax/bear oil mix also. Rolling it works great as a lube without weighing down the cushion wad and pushing it into the shot column.
