Originally Posted By: Jack RobertsOdds are you just don't have the die screwed down enough. A case shoulder length gauge will remove all doubt about what is not right.
Jack
+1 on what Jack said. In my experience, most small base die purchases are made when the trouble really is the shoulders haven't been bumped back enough.
I personally don't care for the "run of the mill" case length gauges on the market, such as the Wilson, Dillon, etc. These will let you know if your cases are "within spec", but not much else. Much better is the Hornady case length bushings that fit into the same holder that works with their OAL gauging system. You can measure one of your fired cases, take a measurement, then adjust your die .0015-.002" less than this measurement.
Works like a charm, and will probably prove that a SB base isn't actually needed.
Mike