Posted by Parashooter.
>>>I believe those who assert that radial expansion contributes to the kind of head separation commonly encountered by .303 reloaders are mistaken. Radial expansion puts the circumference of the solid case web in shear, not stretch - and it does so in a completely different location.<<<<

The case pressure ring material has to stretch radially until it it constrained by the chamber. There is some bending since the stretch occurs at an angle due to the proximity of the solid head. However this still results in the pressure ring being stretched buy the difference in diameter of the case and the chamber as well as the forces that stretch the case along it's longitudinal axis. Stretch along the relatively long longitudinal axis has the opportunity to get spread over a long portion of the case length. The radial stretch that occurs to the pressure ring area is concentrated over a short distance increasing it's damage to the case wall. If there was no stretching caused by the difference in diameters it would be possible to use a much smaller cases head with no consequences. We know that is not possible.