I went to the range today and I lit off a bunch of .308 Win loads made with Win 748 and I noticed that the cases were coming out pretty messy - a lot of soot and I'm wondering if it's the powder or the cast bullets that I've been shooting. (Maybe there wasn't enought pressure to get a good gas seal) On Tuesday I shot a bunch of other loads that had IMR 4350 behind them and I didn't notice mess. The smoke from the 748 also seemed to be a lot thicker versus the IMR which didn't seem to have any puff of smoke after my shot. I was watching "Tales of the Gun" on the History Channel a few months ago and when they were talking about the M16 they said the switch from stick to ball powders (combined with the jungle climate of Vietnam) caused the rifles to gum up quicker - any truth to this? I'm fairly new to reloading and my experience with different kinds of powders is limited.