Uncharted: The Nathan Drake Collection: Side Arm Master
Uncharted: The Nathan Drake Collection™
Side Arm Master (BRONZE)
Defeat 30 Enemies in a Row with Your Side Arm #PlayStationTrophy
You may get this during normal gameplay, but it's likely that your best bet for it will be to wait until after you've finished the game and load up Chapter 5, London Underground, on Easy. Pistols will be pretty much your only option for most of this chapter, and you should have just enough enemies to kill before you finish it.