Originally Posted by cummin_un_glued
Talking about similar cases and why i used 7mm rem mag data. I read over on another forum about using 7mm rem mag brass resized down to 257 wby. I gave that a go the other night and it worked just fine. After light trimming the only difference i noticed besides the head stamp is that tge neck is 050" shorter using the 7mm brass. I just shot some of them yesterday to finish forming them. I will try to post some step by steps later this evening for those interested. I will probably put it in its own thred.
I thought about necking up the 270 mag brass to .308 once. I figure that the 7mm mag will push a 160 grain bullet to 3100fps without too much trouble, then the 30 caliber ought to be at least as fast with the 168 grain bullet. But then discovered that a .308 Norma is virtually the samething! Oh well! But one could form cases out of 300 Win mag brass, and move the shoulder out about .06" and get a longer neck at the sametime with something like a 30 degree shoulder angle. It would be a far better round than the .300 mag with similar velocities untill you got over 200 grains when it would take over with the longer neck keeping the base of the bullets out of the shoulder. But of course somebody somewhere has already done it a couple times over