Resident Evil Revelations 2 - Line 'Em Up! Achievement / Trophy Guide

Resident Evil Revelations 2 Line 'Em Up! - Defeat two enemies with one shot in the main campaign.

At the Beginning from Barry's Campaign you go from outside to inside through a Gate. Inside use the Magnum Python and go forward. In the next Room 4 Enemies appears, wait that 2 or more Enemies in a Row and shoot.

Achievements / Trophies

Line 'Em Up!
Defeat two enemies with one shot in the main campaign.

[winneryeahmate]

Every time Barry starts a campaign in Episode 1 (after the first playthrough) he starts with zero magnum ammo; how do I get some ammo to unlock this trophy?