I agree that there is definitely a difference in case capacity with the aluminum having less space. That's why I went with the load I did. I wouldn't try it with anything near max. Modern guns are designed to contain a case failure and I've had brass cases fail many times without breaking the gun. Usually it is metal fatigue that makes the case fail. That's the other thing with the aluminum reloads. Aluminum acts differently than brass and I don't know how an aluminum case would tend to fail or how much work hardening it would take to create a problem. That's why this experiment will be limited to only one reload. Of course the question of how many times an aluminum case can be reloaded may be revisited at some point. If I survive, I will post my experiences! Anything that happens above the web is going to have very little impact but if an unsupported head fails, the pressure is going to be vented into the gun and the potential for damage goes way up.

This is a good example of a brass case failure. This is a 44 Magnum that separated in my 629. It was definitely caused by metal fatigue from resizing the case too many times. Of course the gun did not fail and the only issue was getting the broken case out of the chamber.