Ive been using TG, and N-320 at very lite loads to see what I like? My ? is that Ive noticed that my barrel is the dirtiest Ive ever seen also its after about 300 rounds or so. Its leaving a thick deposit of sut in the riffling and its very difficult to clean out makes cleaning abit of a pain now. What is causing this and does it have any ill affects on my accuracy while shooting ect? I know that lite loads are dirty but that dirty? Also I have a feeling that N-320 could be causing it and not the TG Ill find that out tomarrow. Thanks for the Help.