Seeker Gun

The Seeker Gun, from Ratchet and Clank: Going Commando can be bought on Barlow. It fires a somewhat slow-moving missle that moves in a straight path until an enemy gets into its range, then it engages a quick homing attack, delivering a powerful blow to the enemy. This weapon is great for shooting around corners or hitting targets far away that you can't get close to or are too hard to hit.

Upgrade
The HK22 Gun shoot three homing missles with a stronger attack and better range.