Fortunately, every weapon in Icar has an anti-gravity engine on just like cars and space craft. The field reduces its mass and helps you carry it, swing it about and aim.
So buying a weapon isn't a valid excuse for not going to the gym...bummer Is the field's strength variable or fixed to the size of the weapon? Would one be able to jump onto it and glide along (while shooting, of course)?
It's fixed to the form of the weapon. People have tried to make them into vehicles before but the result is slow and not very useful. Must better to start with a car, bike (or Zipper) and pack it with guns.