I got bored the other day and was playing around with some different cases and dies. I ran a .357 mag. case into a 30 mauser form die that gave it a 15 degree shoulder and necked down to .308 cal. Has this been done before? I konw that it has been necked down to .17 for the .17/357, .22 for the Jet and .257 for the .256 win. mag. so I'm sure the .308 route has been done before. Kind of a lengthened, rimmed .30 mauser. Just wondering what kind of ballistics this round would have with a 150 or 168 grn. BTHP. I'm sure it would be subsonic, possibly like one of the Whisper cartridges. Anyway, thanks for putting up with my ignorance.