I found a random youtube channel a while ago where they replace buck shot with random objects and see how they fire and how accurate they are. Im certain I seen curving on irregular objects. Imagine a bullet made up of two different materials with one half being heavier than the other. If you shot it from a rifled barrel it would spin (and destroy the barrel probably) but once it left the barrel it would begin to spin on a different axis and start curving. Well I think so anyway.
If you were traveling at the speed the speed of light and you suddenly changed direction would you still be affected by inertia? On the one hand inertia affects all mass but on the other hand your also in your own time zone and while you'd still be subject to the same laws as everything else the time it takes to have an effect would be different right?