This achievement takes place during 2 levels:
1. During EXHIBITION, you'll come up some stairs to a populated area. You'll find two adults with a teddy bear in between them sitting on a bench in front of you. Walk up to the male
2. On RIGA, go down the stairs to find a little boy in the doorway who will tell you that he can take you to your objective for 1 military grade bullet. Make sure to accept, and give him the round.
3. On RIGA, make sure you give some military-grade ammo to the beggars which can be found around the common area on the level below the bar where you start the level.
*Posting for Maka91, because he is only playing the digital version.