Would it be practical to make a 22 caliber wildcat cartdge that would hurl a 55grain bullet at 6000fps.?If so what case would be ideal 300Win,300Rem Ultra,300 Warbird,etc.

It would be practical if you like reboreing barrels

And just what 55 grain pill available could take the heat? VAPOR TRAILS on the way to the target board!! GHD

I'm not certain but I thought expanding gases from current smokeless powder did not expand much faster than 5000 fps but I'm not sure of that number.

You would need some new generation propellant.

No.

But you might get a 55 grain .30 cal up to near that speed.

For purposes of research on small particals at high speed impact, a number of years ago a laboratory used a stock Remington 700 22-250 with nylon bullets in the 10 grain range and a case full of Bullseye. The case was not reusable after one firing, the barrel was a smoothbore after a while, and the bolt had to be hammered open. But the action as I recall, withstood the torture rather well. I think muzzle velocities of the little nylon projectile were in the 12,000 fps range. They were also fired in a vacuum (to negate the effects of wind resistance and mimic tiny meteor strikes on the skin of a spacecraft).

I thinkit is morefun to shoot the 55 grains at a nominal velocity and mimic meteors hitting varmints!!! GHD

22-243 Modified:
http://www.accuratereloading.com/22-243.html
5278 fps
Is that good enough?

You might need to look into using sabots to achieve this. Not sure how they affect accuracy, but it would certainly broaden the possibilities.

Patrick