30 Kills: KAL 7 Trophy in Uncharted 3: Drake's Deception

The KAL 7 is one of the first rifle weapons you encounter in the game, though after this it doesn't feature again until much later in the game. Though it has a high ammo capacity, the accuracy is poor and is much better served as a close quarters gun. You will first encounter it in Chapter 5 - London Underground. There are a couple of decent farming spots as follows:

Chapter 5 - London Underground

As you exit the depository and back through the underground area you are ambushed by goons. Most carry either a pistol or a KAL 7, pick all the KAL 7's up and continue to use it in short bursts to clear your way out of the area and into the service tunnels, then restart checkpoints as required.

Chapter 12 - Abducted

In the area where you swim around the barges and earn kills for the Land Shark trophy are a number of KAL 7 guns. There is one on the first barge you get to along with a grenade, pick it up and drop as many goons as you can before restarting the checkpoint if extra kills are needed. Just remember that you can't use this gun in the water so board one of the boats and wait for enemies to come to you and also any you can get from a distance, there's enough enemies here to satisfy this criteria in just a few restarts of the checkpoint.