I say check your crimp. When using the slower powders hard crimping is needed for good start pressures that as close to the same with each other as can be had. Your crimps should be at the point of not quite buckling the case, just almost. That will also help with a lot of the unburned powder. If there is just a tad bit of powder, and everything else is working shoot them.
Though I am going to say try crimping a tad bit more. You may have to sacrifice a case, and bullet or two to get it right. Oh and make sure your brass is trimmed to the same length to get a crimp in the same spot with each one.
No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.