The reason why 777 can be bad in the Knight, or ANY muzzleloader in fact, is because of eratic pressures and velocities that can result from pressure during loading.
I use 777 in my Remington revolvers, and, and when I load the chambers with too much pressure, I begin to get erratic velocities. When I load them too lightly, velocities drop, all the way low. There was one cylinder-full I let loose at the range,using a Beta Chrony, and discovered that some of my loads were averaging at about 1100 feet per second, while another chamber pounded out about 850 fps.
With 777, you have to trust your instincts, on how much pressure you put on your load. The substitute tends to act a little like smokeless powder, combustion wise, but I find it very useful, little smoke, and little crud.
American Pioneer has some good marketing strategy, but their product is mediocre. APP always give consistently lower velocities than all other powders and substitutes when loaded by volume comparison. 777 is actually a bit cleaner than APP.
There is yet another new substitute on the market now, I believe it is called Shockey's GOLD, made by famous hunter Jim Shockey. It reportedly performs a lot like 777, but I didn't try it. GOLD is available at any Cabelas or Bass Pro shops.
It seems like nowadays, so many new BP substitutes are appearing AND disappearing from the market, it is so hard to keep up with them. Just a few years ago there was Cleanshot and BLACKMAG3 BP substitutes. They diappeared only after two years on the market, reasons unknown. It was kind of like the late 1880s, when so many different companies suddenly sprang up overnight in the US and Europe and advertising the most cleanest, meanest, and baddest brands of smokeless rifle powders, things that can take down elephants with a single shot, no matter how skilled the safari hunter is, Nitro Express sagas, and thousands upon thousands of other things. I have a few of these newspapers from the United States at the turn of the century, and they are really a great fun to read, all those concoctions, miracle cures, and smokeless cartridges.
Otherwise, stick to Holy Black, the real stuff.
