alsaqr= Wasn't there a article that came out in one of the muzzleloader mags. that when using 777 with a 209 primer that it caused the powder to move down bore before the powder ignited causing the crud ring you mentioned? Pete
Yes, i read an article that claimed a regular shotgun primer caused the powder and bullet/sabot to move before the powder ignited.
Winchester and other companies came out with primers that were supposed to remedy the situation. Winchester 777 primers only made my 777 crud ring worse-much worse. Not sure I believe their theory.
I've seen a small crud ring with other powders too: Pyrodex, JSG and Pinnacle will leave a small crud ring where the sabot sits if one does not get all the oil out of the bore before firing the gun.
777 is a really good powder but is awfully dirty. It makes very good groups if one swabs the bore after every shot.