Riot Rocker Trophy in Uncharted 3: Drake's Deception

Ordinarily, Riot Shield carrying enemies are best dispatched with a well placed grenade but for this trophy you're going to need to be a little more hands on. You won't encounter any enemies of this kind until Chapter 9 - The Middle Way, during your escape from the complex in Syria. After the cutscene where your party run into Talbot and his goons have a Mexican stand off, you will begin your escape with a wounded Cutter. The next wave of enemies will have 2 riot shield carrying enemies, try and trim down the enemy count but leave these guys active and let them separate, though keep in cover as they both carry an Arm Micro that can tear you down fast. Once they are in decent range, blind fire at the shield until they go into a cover pose with the shield above them instead of upright in front of them. This is your chance to score a kill so dive out of cover and run towards them, pressing twice, once to run over their shield and another immediately after to choke them to death. This is a confirmed kill and counts towards the tally, repeat this on the other guy and restart the checkpoint as required.

There are also another 2 Riot Shield enemies in the very next area who also offer up a good opportunity for these kills but it is on a narrow walkway and they walk single file so the trailing ones tend to get you when you are trying to take out the first so isn't any easier than the area before it but is still worth a try if you want to farm them.