The sniper cannon was a device featured in Jak 3. They were large mechanical arms used by the KG Death Bots and stationed throughout the Industrial Section. Jak destroyed these by diving ( + ) on buttons stationed around the base of the cannon in the mission "Destroy sniper cannons". Jak had to deactivate each button before the former button went back to an active state after a given length of time, if all buttons are pressed in time the power core for the cannon will appear which can then be destroyed causing it to stop working.
The cannon takes a short time to lock onto a target, but when done will accurately fire a short burst of shots at its intended location.