
This is how a full ammo box of 800 5.56 NATO rounds arrive. It has no magazines at all. You need to load them yourself.

They have a stripper clip that attaches to the magazine, and let’s you quickly put in 10 rounds off a strip.
They don’t send that many magazines out to forward bases. All soldiers are required to police and inspect their magazines, then reload them.
I’ve seen that once. Our unit was attacking an enemy checkpoint at night and while I was shooting my rifle, I could see another soldier to my right firing his marksmen rifle, a SIG-Sauer SSG-3000, cal. 7.62 X 51 mm.
I was fascinated by the sight of his black silhouette against the night sky and for a while, I even forgot why we were there. He shot a few shots, the enemy shot back at him and then I saw that he changed mags and let the empty magazine drop to the ground.

Two guys from my unit in Kosovo. The first one with the SSG.
Someone shouted an order to retreat but before I joined my squad, I went to the place where the guy had lost his mag and picked it up.
We went to a nearby Albanian village where we had a debriefing in a farm house. I saw the shooter sitting on a couch and sat down next to him. While some commander was talking, I softly pushed my elbow in my neighbor’s side. When I had his attention, I gave him his lost magazine.
He didn’t thank me, although the SSGs came with only two mags and he had thrown away half of his supply of magazines. Instead, he looked at me like the idiot he was.
This was the only time in my life that I saw a soldier throwing away his empty mag. You never do that, even if there’s a truck with 100,000 mags right behind you. It’s unprofessional.
I wouldn’t unless I had to.
My M16A2 from the Gulf War worked best when I had a magazine to load it with. Tossing away mags is a great way to make sure that you’ll run out of ammo in the next action. I personally didn’t go through a full mag in that war, but I’m I wouldn’t have tossed it away if I had the choice. I would have slid it back into my ammo carrier or a pocket and moved on.

One thing you miss in movies and other media is that you actually have to LOAD your own mags and they only give you so many mags! Yeah, you can have lots of loose rounds but you might only have a handful of mags! You need those things!!!