Hey guys. I was just wondering what the maximum velocity for a bullet would be? Doesn't matter what bullet or cal, I just want to know what the fastest velocity you can get a projectile is. I read somewhere that most powders only expand in the 5000 fps range but I also have heard that the 120 smooth bore on the Abrams shoots a saboted projectile at 6000 fps+.

Mostly just curious...

I think PO Ackley or someone he worked with necked down a .378 weatherby case to .22 cal. I think it was called the earsplitter loudboomer?. Anyway if I remember right it got out of the bbl around 5000 fps. I don't know if the bullets held up though. There may have been a past thread here that talked about army ordinance doing something similar but with a smooth bore just to see what speeds a small arms bullet could be launched at.

The eargaspliten loudenboomer only lasted a few rounds before it had throat erosion.

Last I heard, the actual MV of the 120mm APFSDS long-rod penetrator round of the M1 tank main gun was still classified, but was given as "over 1 mile per second", which is cerainly well into the 5000 FPS + range.......

You hear tales of around 6000, using particular powders and very light bullets.

But all this presupposes regular double or triple base powders, in a conventionally designed gun. You _can_ do much better, by using gunpowder (of whatever sort) to drive a piston which compresses helium behind your projectile. This is called a "light gas" gun, and they have much higher muzzle velocities.

Then there are other propulsion mechanisms, like rail guns and so forth. With them, speed of light is essentially the limit. I know I've read of 30,000 fps with a rail gun.

Pertinax

Have a try at this.
www.scitoys.com
go to magnetism column and then click on Gauss Rifle. Its only a small demonstration but would be cool for hunting grass hoppers!

Specualtion on the bullet speed in a given wildcat cartridge is just that speculation. The 220 swift shooting the 40 gr. bullet at 4200 fps is plenty fast for me. The Army did some testing and achieved a velocity of 11,000 fps from one experimental cartridge. My speed machine has shown me many times that listed velocities are not accurate. The accuracy load in my Browning 300 magnum gives me 2800 fps with the 165 gr. bullet and my loading book says I should get 3160fps. That is 360 fps slower than the book said I should get with the same powder charge.
One thing is certain you better own a barrel company if your going to shoot those high velocity wildcat cartridges. The 378 Weatherby necked to .224 diameter would have no barrel life or accuracy either. That would be one over bore cartridge and a fine conversation piece.
I have seen written reports of 30-378 Weatherby rifle bores being shot out after only 600 rounds. Any cartridge that will consumer more than 100 grains of powder per round has to be a barrel burner.