By adding bipods to the the game it would increase the accuracy of the rifle some amount but of course the player would have to rest his gun on a block, two blocky high if standing and one block when crouched.
To make sure it is not over used it needs draw backs. It would have to take one second to put down and take back up and restrict the players view and only allow them to look as far as a 45-60 degree angle from the side of the block. The player could be forced to look down the sight while using the bipod or have the gun sit in the centre and be able to look down the sight, like whats done in battlefield.
And of course I would prevent the player from moving and ducking.
I would be excellent for people in a defensive position.
Just an idea ;D