Richard,
Thanks for the response.
The primers fall out when the primer pocket grows a little in diameter.
It is a real problem, and I chose one of the worst case cartridges.
Here is a picture of some primers falling out:
http://www.thehighroad.org/attachmen...=&postid=49766

Here is another:
http://www.thehighroad.org/attachmen...&postid=333274

Can you see how the cartridge has a narrow ring near the base?
The is the extractor groove.
The primer pocket is inside of that, so the brass is thin there.
Clark