Originally Posted by Davers
One could just neck-up the 7.62X39 m/m to .357.
A guy down in your old stomping grounds has done exactly that, creating the 358 Gremlin for use as a deer hunting cartridge in Indiana. However, that does not give you a straight-walled cartridge, which I think is the intent of the OP. David White (ASSASSIN) is working on a 222 Remington blown out to a straight-walled configuration that basically makes it a 357 Super Maximum. It exceeds factory 35 Remington numbers by a couple hundred feet per second.