Don't suppose anyone else has this cartridge..........a necked down .308 Rem BR case with .22 caliber bullets. My rifle is a M98 with Shilen 1:14, don't shoot alot as it gets hot in less than 5 rounds. r in s.

Well Ray,

Maybe you have now discovered WHY you are the only guy in Town with one!

Ray,
Mine is based on a full length 270 case. Load it with the right components and it is a lot of fun and will do work beyond what you would reasonably expect. The idea is to minimise friction and to seal the barrel against gas blow by as effectively as possible. I run 40gr monometallic bullets at 4700fps and you can see the result here. I shoot mine a lot and use it for cull hunting and meat harvesting.