Well, since its relying on electromagnetism and not gunpowder, I suspect the kick is far less than one should suspect. At least as far as I understand the technology.
You aren’t directing an explosion, that wants to expand in all directions here out a nozzle here, you are progressively moving a projectile with magnetic force faster and faster over a short distance.
Think of it more along the lines of a SUPER roller coaster magnetic launcher, than a standard gun. Just far more powerful, and extreme.
Mike
Ignore my roller coaster analogy, that’s a different technology... but still recoil will be far far less a standard gun would be for equivalent velocities.. of course gunpowder could never reach the full velocities of a rail gun anyway.