I hope it's a cure. I like the M dies or expanders. I use them in my Lee single stage press. I had to use a spacer to get the correct depth of the M expander for my 9mm shells in my Lee dies. But, then I noticed that the die was putting a bulge in the shell. It seems the expander is too long. So I made it shorter and that seems to work. I ground the end of the M die making it narrower and the bulge was gone. Do you think this will work out OK? I ground off the area marked in red on the M expander, in the picture. The arrows point to the area where the bulge appeared.