Re: Rail guns (was: US SOCOM desires...)

["Robert J. Hansen" <rjhansen@xxxxxxxx>]

> Momentum is conserved as well as energy, though. You don't instantly
> accelerate the soldier so as to convert all that recoil into kinetic
> energy - some of the energy goes to other things. As far as I have been

Yeah, but figuring out just how much impulse is conferred to the soldier
momentumwise was a little more calculus than I cared to do at the
moment.  It was enough for me to say "you want to make a shoulder-fired
cannon with 30,000 J of kinetic energy?  Uh.  NO.  Next question."  :)

> able to discern, recoil works a lot more on momentium than on energy -
> which suggests that, for a given energy, a light fast round will have
> less recoil than a slow heavy one.

True--which is why the .223 is much preferred by many soldiers over the
.308.  Far less momentum.  Fire off a 7.62mm/.308, and you *know* you're
shooting a rifle.  Fire off a 5.56mm/.223, and you've got a pop-gun made
by Mattel.