looks to me like you are expanding too much. Try expandng only to the first 1/8" or so of the case and make sure that all cases are Exactly the same length. You just need to give the bullet a slight start into the case. It looks like when you are expanding that much, you are putting way too much pressure on the rest of the case.

When I expand my .45 ACP, I put the expander die (RCBS) into the Rockchucker Press. With my RCBS carbide dies, the expander has a knob at the top of the die that allows me to adjust the expander ball. I let this out considerably after the die is in the press and secured. I then put an empty and resized case into the shell holder and raise the shell into the expander die. Then I turn the expnder ball knob down until there is contact with the case. I then lower the case back down and turn the expander ball knob in another 1/8" toward the case. This should give an expansion to the first 1/8" of the case when you raise it back up again. Check it to make sure. When everything is right, tighten the expander ball knob and continue with the rest of the cases.