Would you really be able to get 7500fps. from the 22WSM I thought the highest attained velocity you could get with smokeless powder is 6600fps. correct me if I'm wrong?
I think they were just being sarcastic. Yes, with conventional propellant-driven projectiles, ~6500 fps is the maximum limit. This is the maximum rate a gas can expand at, and a bullet couldn't go faster than the gas that's pushing it. There have been military and NASA projects pushing projectiles out at over 20,000 fps, but that was using electromagnetic rails instead of gunpowder, and very complex, heavy equipment.
Starvos: Think of it this way. Such a cartridge would blow molten drops of barrel steel downrange about as fast as the bullet!! Way overbore!! Even a regular .30/'06 case holds too much powder for a .22 caliber bore. The .22/250 and .220 Swift are just about max for .22s, unless extremely log-for-caliber bullets are used, and then you need a fast twist. The heavy bullet/fast twist combination thwarts the hypervelocity goal.
