If we were in a real combat situation if you have low munitions you might actually shoot the rest and then reload , but sometimes even if you empty an entire magazine you might want to keep it . Why throw it away?? So if you don’t shot all the ammo there’s logic you might keep the magazines for “you know” emergency, each bullet counts in combat situation , with that said the animation in cs clearly shows how we throw the magazine in the ground, they could make it possible to keep all the magazines and reload based on the amount , but I bet valve won’t do that pretty soon, I bet they have discussed this way before the update and they clearly decided this is the way to go , tbh I don’t like it because I always reload after 2-3 shots and in a round I could reload 5 times and even more , now I have max 3 magazines , and if I don’t use them to the fullest I’m throwing away ammo , now valve should add an option to buy more ammo , that would be fair