Just a little known fact I wanted to share. I sighted in both my inline muzzys in March and they were hitting beautiful. I went out the other day and the target looked like I was shooting buck shot, my groups were anything but groups. I tried and tried. I ran out of powder and opened a new jug of 777. Well I got to tell you with the new powder I ended up readjusting my scope back to the original settings and was again grouping like a champ. After I started to investigate and found that after you open a jug of powder and break the seal it starts absorbing moisture from the atmosphere which will cause the problem I had. So if your out at the range and find you are having this problem this just might be why, Good Luck with your white smoke!