That top one is the exact photo the .50AE icon is based on, though of course I modified it, several times over:
Action Express v2
Action Express v3
Action Express v5
Hydro Shock v2
Hydro Shock v3
Frangible v2
Frangible v3
It's one of the earlier ones and probably the series I'm least satisfied with overall, otherwise I'd be telling you to take a hike
It was designed to be instantly recognizable as an icon. I had no idea I'd be making textures to go along with it at the time, so it's fairly plain with large text which helps it show up when shrunk. When I finish up some other S.T.A.L.K.E.R. modding projects I may try something more complex with it. For now, just deal with it >
I won't be re-doing any existing vanilla ammo types.
I've seen the Federal brand boxes before. They're not really suitable. Their subtle color pattern looks like muddy garbage when shrunk down, and if you take that away it's nearly the same as a plain box, just blue. The trademarked details, such as the logo and the bullet stamped with 'personal defense' cannot be kept. If I end up drawing over 100% of it, there's no point in using a photo source to begin with.
Magnum Research has some amazing modern retail packages for .50AE that are built out of metal or plastic. They're what I wanted to use, but I'm not going to buy boxes of magnum ammo just to get suitable photos of it