So the 400-350 is the same basic case too. Brings up a gripe I've had for years, how come no brass? You can get 600 Nitro brass. For every 600 Nitro around there must be at least a hundred rifles in the 400-3xx class.

Bertram makes brass so labled, but you can't get it in the chamber with a mallet nor in the sizing die without a hydraulic press and you wouldn't get it out without tearing the rim off. (Unless the die split.)

Don't forget the 400-360 rimless. Still the same case. Known examples of the 400-360 rimless seem to be made up from a 400-360 rimmed case with the rim turned off in a lathe.