.22 What!!!???

[Catfish]

The round you are refering to is more fiction than fact. While I`m sure that there have been .50 cal. round necked down to .22 cal. and had barrels chambered in it, the fact remaind that it is totally impractial. I did see a barrel that was chambered in the 50 bmg necked down to 6mm, ( .243). The guy that had it said he was only able to get around 6,000 fps. from is. With the amount of powder required the round was simply way over bore to the point of being silly. If I rember correctly, that around 7,000 fps. is the fastest you can push a bullet with gun powder due to the physics involved, and that is in theory.