It depends on the speed. If we're talking the "theroetically idealized" speeds (i.e. %10 the speed of light), then, assuming the round survives the acceleration, there could very well be some energizing of the air around the muzzle. I don't know for certain, and to be exceedingly candid, I've actually never heard of this phenomena as being a possibility.
I actually did some fairly in depth research for a paper on direct energy weapons, and one of the best sources I came across was a book called "The E Bomb". That combined with one or two websites reccomended here a few years back, gave some interesting insight into the feasability of direct energy.
Supposedly the physics of heating the barrel needs to be overcome, but from what I've read it's more likely the power scaling factor, and hence deployment onto refitted hulls; i.e. FFs and DDs.
I actually did some fairly in depth research for a paper on direct energy weapons, and one of the best sources I came across was a book called "The E Bomb". That combined with one or two websites reccomended here a few years back, gave some interesting insight into the feasability of direct energy.
Supposedly the physics of heating the barrel needs to be overcome, but from what I've read it's more likely the power scaling factor, and hence deployment onto refitted hulls; i.e. FFs and DDs.