I've been reloading the 300's with IMR 4198 for years without seeing any unburnt powder residue. Accuracy has been outstanding. I know some of the people that use Re7 with the lighter 300 gr bullets have mentioned that problem; but it doesn't seem to have any affect on anything. I'm using Re7 with the 400 gr FP's right now, and haven't noticed unburnt residue in mine, although the guy who gave me the load I"m using said he had some; but the load was extremely accurate. It is that. Go figure.