I've always wondered if there could be a use for empty magazines. Well I've came up with a concept, and I want to know if it's possible to put into the game.

You buy a special gun (Preferably an ordinary assault rifle), and you're shooting some guy who's in a ditch when you run out of ammo. Your magazine falls to the guys feet, and you must take cover while reloading. in this time you could press a button, and it sends a signal to the magazine to blow up, finishing off the wounded foe. Is this possible, and how would I do this? Also, could I disable previous magazines that didn't explode. I'd hate to run into a situation where I shot a bunch of magazines off, and they all blow up when I only want the most recent one to explode.

Oh man, this takes me back. Way back.
One of my first mods [unreleased ofc] was a Pancor Jackhammer shotgun. I was || this close to making a new thread to ask if it were possible to make magazines that exploded into a direction when stepped on based on how many shells were left when you reloaded. Obviously impossible before Lua, still probably damn hard and hacky. Maybe I'll try it some time.
But anyways...

You need to apply a copy of the C4 bomb script to the magazine's MOSRot gib, and then apply a copy of the C4 detonator particle script to the particle of your detonator.

But, you need to make it use different lists, and I'm not certain what entails in that, as I've never used or understood CC Lua lists.
I'll go give it an intuitive attempt though...
Lua on magazines seems screwy, but I can circumnavigate that by gibbing it into a MOSRot upon impact with terrain and dealing with said MOSRot instead...
Almost there...
Done.
This should be fairly easy to incorporate/modify into whatever you want. Mag gibs into MOSRot, MOSRot has its script, and a detonator device fires a particle with its script, which gibs the most recently spawned of that MOSRot. [the mag gib]
A bit of credits would be nice if you use this, just a mention or such. Forget that, too simple to merit credits, it's just a reapplication of [presumably] TLB's C4 code, even if it took me a while to test it and figure to use a MOSRot mag gib.