Mac,

Don't be fooled about the strength of the .444 brass. It is beefed up to be used in relatively springy lever action guns.

You are certainly correct that a .243 Rimmed can be formed as you said. In fact, I had a hunting buddy who chambered an antique Brit single shot action for a .22/250 Rimmed, and he made his brass out of .444.

Wonderful stuff, that .444 brass.

Curl