777 is faster, less variation in fps = usually better groups, more corrosive, dirtier, 777 has crud ring problems in some rifles which can make loading a fast second shot all but impossible... all that being said, I love the JSG Sticks in my Pro-Hunter. It's so easy to clean it's just funny,,, my 100 yard groups stay at less than two inches out to 150 yards in any weather,,, and it is a proven powder on the world stage of hunting,,, last but not least Jim Shockey is cooler than a guy dressed in a deer suit.