For instance, I suspect the most power efficient mass driver (for nickel asteroids) or a large railgun/gauss gun may be the one with the longer barrel (vs. shorter barrel which means the acceleration must be piled on faster meaning likely a higher net energy input and perhaps more losses and a much heavier set of coils/etc).

I also think that might be true with PAWs/CPAWs (particle weapons) as they nowadays take a long acceleration path (see LHC in Europe!).

Comparing that to a missile tube or a laser, a much longer length.

So? Fair question.

If you are trying to shoehorn some of those systems into the smallest volume of hull, although the rules don't address this, I'm thinking those sorts of performance realities and weapon system geometries would mean that you could put it into a smaller tonnage conical/wedge or needle type of hull vs. a sphere or cube layout because you'd minimize the amount of other space around the weapon systems which would have the run of the ship.

Fighter launch tubes probably also fit that category.

Does that seem like something that might be reasonable to expect?

And would it be more reasonable without gravitic controls (which might be used in some high TL weapon systems like railguns or mass drivers)?

Meson guns I'm less clear on but if you need to accelerate the meson particles, I'd guess it too would have the same issue.

Obviously, a big enough cube or sphere could support one, but it'd be very large in overall volume. If you got a needle, wedge or cone, you'd have less excess space in order to meet the needs of a long acceleration path for the projectiles or particles.

Tom

Tom