Whatever the opposite of spinning in one's grave is, Gerald Bull would be doing that right about now. This is just Project HARP recapitulated -- and I'd be willing to bet that a significant amount of the data behind this came from the Iraqi superguns Bull designed.<p>It's not detailed in the report, but I wonder if they've considered the "watermelon seed squeeze" method (wherein the projectile flies through a combustible gas mixture in a weakly-sealed barrel tube, compressing the mixture with its nose cone, creating a combustion zone about two-thirds of the way along a "spitzer" type projectile, thus applying the expansive force inward against the tail cone). That would either create one hell of a high-speed projectile, significantly reduce the barrel length required -- or even allow tolerable accelleration from, say, a linear electric motor's initial shove by simply stratifying different gas mixtures along the launch tube to control the combustion velocity. (Cheap 1-mil poly film would maintain the separation of gasses well enough and fail safely.)<p>Man, I has to go into rocket surgery. Or maybe double-nought spying.