You’ll find this magazine in southern Libertad province, inside a Unidad combat outpost. Surprise! It’s full of soldiers. The accessory case is in the armoury, just inside the entrance at the west.
If you use a drone, it’ll get jammed from the nearby gas field, but it’s still operational at the western side of the outpost. Take out the sniper in the tower first, then you can decide how to approach this. I entered through an open gate on the east side of the fence, but then you need to manoeuvre around the northern perimeter to the armoury.
You could patiently sync shot and take down each soldier as they move around and isolate themselves, or use a distraction such as a flare gun off to the south to move them from your path. Beware – there’s a soldier sitting at a desk, inside the armoury, to the right of the entrance!
This magazine is for the SASG-12 only, found in Agua Verde, extending its standard 5 rounds, which is tiny, to an awesome 30 rounds! 30!!!
The SASG-12 is an automatic shotgun, so you can hold the trigger and it’ll pump out rounds, making it a pretty incredible gun for close quarters, so check that out, cos it’s an amazing shotgun!