Trying to tune up a mec 9000 in .410 bore. I'm using AA hs hulls, win 209 primers, 13.3 grains of Lilgun, and PC orange wads. The hulls are once fired hulls and look good before reloading after I reloaded 2 boxes I noticed about 7 shells had split brass. I did some research and it appears the split is happening during the deprime/resize stage. Do I have trash in the collet or is there some adjustment I need to make.
Any advice would be greatly appreciated.