Particles moving at the speed of light have no mass, and therefore don't respond to gravitational fields directly. What they do do is follow a straight line - regardless of whatever peculiar behaviour 'straight lines' happen to be indulging in at that point in space. And they can get up to some really peculiar antics indeed under the influence of gravity. Massive particles, even near c, _do_ respond directly to the field as well as following the geodesic, and so are always deflected more than photons are. It's the nature of the particle that matters, not the velocity per se.
WLBjork wrote:Possibly.
However,I would submit we see a certain consistency all the same.
The thing is, sidewalls (and the particle and radiation screening that fill the rest of the volume between ship and sidewall) aren't "hard" energy shields, but gravitational fields.
Slow moving particles, such as missiles and even plasma torpedoes get torn apart and deflected from their course. That will not require additional energy or effort.
Particles traveling at light speed, such as photons,are fast enough to get through with only minor deflection/dispersion. Thus a nuclear weapon that generates a lot of gamma radiation that is carefully focussed can penetrate a sidewall.
Of course, whether gravity can really be focussed so precisely in that way is another question entirely. They've managed it in the fictional Honorverse though, and that's all that's important.