Yes.. its called inertia and it has a huge effect. Anytime I am dealing with a fast moving piece of machinery, I have to calculate inertia to know how much energy will be required to start and stop the motion of any moving parts. If you hook up a servo drive or other kind of motor, you can burn them out if inertia loads are greater than the components are rated for. In fact, to my knowledge, inertia would be the single largest variable in determining the amount of recoil.. (although I'm not sure off hand what the effect would be if the weapon was pointed straight down and you had gravity working with you) I'd have to work that one out.

That I'm not sure about.. As I have been told here in this forum that I am mistaken, I always thought the projectile was long gone before any recoil could affect accuracy.