When I took the pictures, i brought back 2 rangefinders, at least 15 piece of 7.62 ammunition, and some weapons too, but they are all gone. Only what i brought back on me, stay in my inventory without modifing. BUT if you go to briefing to start a mission,and when the briefing ends, it take away more items, and make some of them dissapear too.
I suggest to make a large crate at the camp that contains only your stuff that you bring back from missions/scouting and stores it there without the game touches it.