The "What would happen?" thread

[Lone Star]

It wouldn't matter if you necked down a 55-gallon drum to .22 - you'd only get 4500 fps or so...

Rocky's right of course. The limiting factor is the speed fo the gas pushing the bullet, not the amount of powder. A normal average for the gas inside the barrel of modern cartridges is on the order of 4000-4700 fps at the muzzle, and you cannot get the bullet to move faster than the gas which pushes it.

It is possible to increase the gas speed above 4700 fps, but to do it requires much higher chamber pressures and temperatures than our rifles and reloading components are disigned for. More powder at sane pressures just allows heavier bullets to be pushed to the same top speeds.....

References:
Lyman Reloading Handbook, 46th Edition.
http://www.quarry.nildram.co.uk/ballistics.htm
http://www.shortmags.org/shortmags/d...coil_Chart.pdf