I have been loading 20 ga. Winchester AA CF hulls and the end product looks great. I recently switched over to the new(er) style Winchester AA hull and . . . . . . .now I'm experiencing a buckle in the sidewall. My load is: Winchester hull (newer) 7/8th oz #9 shot 15.5 grains of Universal W209 Claybuster wad - minimal wad pressure I've never been able to remember the different types of hulls - straight wall or tapered. Do I need a different wad ?
First thing check stack height. Run a shell through the loader and remove it before the pre crimp is applied. The shot should sit at the bottom of the old crimp. If it is above this area the stack height is too high allowing insufficient room for a quality crimp and you will need a component change. If that is correct move on to the next step. It looks like you are crushing the case wall in the final stage. Raise the final crimp die 1 1/2 turns up and see if the crease goes away. Also observe the rounding on the outside of the crimp. It should impart a small rounding of the crimp to facilitate inserting the shell in the gun. The rounding in the picture looks excessive. Looking at the crimp it looks like you need a little more material for the folds and a little deeper crimp as well. I would lower the pre crimp in 1/8 turn increments to increase the material. Use caution if you go too low the pre crimp will stick on the shell. You can also move the lever up on the initial crimp die. If you put too much pressure on the wall it will buckle. Lower the center post on the initial crimping die to get the depth you want. Move the final crimp down in 1/8 turns to impart the rounding desired.
