crouch. zoom in to the loot under the bed. get it.

@Jack Sparra
i mean that they spawn in very little amount, i have found magnum ammo just one time in the last two days - 1 bullet. in the deep of the Chernarus. i'm pretty sure that this way of ammo spawning is kinda glitched.

it will be fixed in the incoming patch. go get experimental branch, few servers are running it. btw, magnum ammo still not spawning properly :/

1.spawn
2.run to the nearest water pond (look for the map in the internetz)
3.drink water as long as you can click "drink water"

4. ...
5. PROFIT!

with that tip you can run to the NWAF(!) with one canteen of water and one can of food (if you know where to run without getting lost, you can sprint all the time :D).

P.S. Sorry for my bad english.