GEP gun

The Guided Explosive Projectile (GEP) gun is a rocket-firing weapon capable of locking onto targets. It can be reloaded, which gives it a major advantage over the LAW. It must be reloaded after every shot, so users should be in a safe spot before firing.

Very few enemies use it, but Paul will offer it to you at the start of the game. If you don't get it from him, you can find it at one of the security towers in the airfield.

Tactics
The GEP gun is one of the most versatile weapons in the game. It can take out multiple groups of enemies with ease, destroy turrets and cameras, break down doors, and take out robots. In addition, ammo is common. No matter what your character build is, you can't go wrong with the GEP gun.

When using it against turrets and cameras, aim the gun so that the rocket will destroy both the turret and the camera, if that's possible. If you can't, always destroy the turret. A group of troops is much easier to get past than a turret.

When using it to break down doors, make sure to be ready for any enemies that might hear the explosion and come after you.

As a robot-destroyer, it can destroy small and medium-sized robots with one hit. Large ones will require two rockets (unless you have advanced training in heavy weapons), so be near a safe spot before attacking.

The GEP can also load white phosphorus rockets, which set anybody that survived a rocket on fire. This makes it the ideal rocket to use against enemies, so if you're heading into an enemy filled area, load WP rockets into your GEP Gun. WP Rockets are extremely rare, so don't waste them on doors, cameras, turrets or robots!

In-game Description
The GEP gun is a relatively recent invention in the field of armaments: a portable, shoulder-mounted launcher that can fire rockets and laser guide them to their target with pinpoint accuracy. While suitable for high-threat combat situations, it can be bulky for those agents who have not grown familiar with it.