Well fall is comming up so I thought I better start making a list of supplies  and I pulled out my Dillon scale an and made sure it it was ready and I zeroed it and put a 5 grn check weight in and it was ok then I put a 20 grn  in  and it read heavy so I looked it over and every thing looked fine so I checked it over again and same thing happened. I thought I better start looking for a new scale  As I was reading on the new scales  a word jumped up and slapped me, the word was magnetic and it dawned on me that I had my tumbler going and it was about 6 inches away from it.  I went back to my scale and checked it. yep it was ok.  I guess the motor was giving off a magnetic field or may be the vibration of my tumbler.