Destroy sniper cannons is a mission in Jak 3. Super range sniper cannons were keeping Torns men pinned down while fighting in the Industrial Section, he needed Jak to find the hidden cannons and take them down.
The PlayStation 3 and Vita versions of this mission are related to a trophy named "Can Can Cannon", completing this mission will reward you with a silver trophy.
All five sniper cannons are located on top of the overhead walkway (they are marked on the mini-map). As Torn instructs over the communicator they are shielded, to de-activate these you need to dive punch the nearby buttons before the cannon's power source can be destroyed. While doing this you will be attacked by spydroids as well as the sniper cannon itself (the camera will shift into the cannon's field of view), stay out of its reticule to avoid being shot.