I doubt counterstrike was the first game to use this style of reloading, but it’s a massively popular game, people for some reason seem to think it’s realism focused, and so it gives credibility to this stupid design so I’m going to blame it.
In games of this type (most modern shooters), you get a certain amount of rounds of a given ammo type. When you press the reload key, an animation of you sticking in a new magazine plays, your gun is topped off to its full capacity, and the number of rounds it needed to reload is deducted from your total.
IOW, you have a gun with a 30 round magazine, and 100 rounds in reserve. You fire off 12 rounds, and hit reload. The reload animation happens, your gun now has 30 rounds again, and you have 88 rounds in reserve.
This is magical. You effectively have one magazine which you can top off with as many bullets as you’d like in a 2 second span.
It’s so stupid and blatantly unreal that it immediately makes me dislike any game that features it. Unfortunately, most games do, even ones that attempt to give the appearance of realism like CS or cod4.
It leads to the annoying, distracting playstyle where people spam the reload button as soon and as often as possible. You have a rifle with 30 rounds in it and you just used 1 round to shoot someone? BETTER SPAM THAT RELOAD KEY!
It takes me right out of the game and reminds me of how silly it is. I do get enourmous satisfaction when I’m fighting someone, and my teammate comes around the corner and the enemy shoots him, and then I come around the corner and find my enemy in the process of reloading because he spent a few rounds, and I shoot him in the face as he can’t do anything to stop me.
It’s not really much more technically difficult to implement a realistic magazine system, so I assume the fact that most games cater to this is just because it’s what the common idiot likes. But it’s so much more satisfying when it’s modelled properly, like in the first 3 rainbow six games, ghost recon, operation flashpoint, ARMA, red orchestra, etc.