use the setvelocity command to acellerate them, maybe in combination with setVectorDirAndUp.
or simply setPos them down in a very quick loop. (recomended)
PHP Code:
while {(getPos _bullet select 2) > 0.3} do {
_pos = getPos _bullet;
_bullet setPos [_pos select 0, _pos select 1; (_pos select 2)-0.1];
sleep 0.01;
};
experiment with different values to get good result, as gravity is slow in arma when just spawned in air.
Edit, in the above setPos example you can also offset it a little as well in any direction to simulate a arc and not direct drop down, but if its fast i dont see it as anything other than frosting, because noone will probably see it?
Edit: changed alive in while loop to height check instead.