I've noticed a bunch of folks saying they wont use this powder or that because it burns dirty. Now I,m not talking about crusty nasty dirty, but powders like unique 2400 and the like I get good performance out of a few powders that "burn dirty" and have yet to see any detrimental effect to my firearms in a couple decades of using such powders. Unique and 2400 are "cleaner" burning than they used to be but after testing 500 rounds in one session the fouling only became a problem after about 200 rounds and groups opened up. I have seen this with several firearms. the round count varys from gun to gun but over all things are running pretty good. Other than a few kernels in the bore could someone explain the detriment