Re: SMc Cartridge Developement.
The Wby cases have a "double venturi"; neck/shoulder and shoulder/body. The SMc cases have no "venturi" at the neck/shoulder junction.
There was a PS article on this concept about 2 years ago. Look up one called "Carbide toothed beavers" (the only way case forming could be more difficult is to breed carbide......) This article was about M.L. McPherson's idea for the perfect 6mm bullet launcher. He called it the 6mm Thermos. As far as I know, there has not been a follow-up article.