It's been my impression that hot magnum loads of 777 will cause earlier breechplug erosion than most-all other powders -- except possibly Swiss Black FFF. Very-very few shooters use the mighty potent Swiss - so I haven't a clue on how it eats breechplugs. I did try the FFF Swiss fortwo range outings& never had use for it again. Perhaps I should of tried the FF... but I didn't. Now I stick with Schuetzen FFF instead - with one ML of mine.