With the weapon in front:-
The action of driving gently foward will cause the weapon to try to lift .....hard acceleration should make it whack back to behind the bot.
Theres an IF to go with the above.....
IF the balance between the weapon weight/length exceeds the ability of the motor drive torque to raise it ......then it will tend stay in front or behind.
EDIT:- Hard decceleration adds an extra inertia factor.

(Message edited by woody on May 02, 2007)