Best bet would be to listen to those who use 777 powders. If postersdon't include 777 in their posts... disregard them. No other powder will lock up your breechplug like 777 will.
For instance:
I used Gorilla Grease for years with Pyrodex & Goex. It worked fine. With magnum loads of 777 for almost 40 shots, it seized for two days before I finally got it cracked open.... after destroying the front of the breechplug using a 7-16ths socket, breaker bar & PB Blaster for 1-1/2 days. Same with usingonly teflon tape without any grease& every auto grease Wal*Mart sells..
CVA Breechplug & Nipple Grease has a percentage of nickel-anti-seize in it. Check your plug after every 8-9 shots with the CVA. It won't be seized. Keep shooting afterwards- keep checking it.... all day long. It's good stuff! The only other one that I know will work to my satisfaction is this one below.
http://www.sportscareproducts.com/detail.php?product=80135-1
or product #56614 here below
http://www.labsafety.com/store/product_group.asp?dept_id=8835&parent_id=352