It bugged me at first but the way I see it (especially in handcannons) is that you aren't firing bullets, you're firing some sort of energy. That's why the cylinder looks like a battery and no bullets are visible. That's how I justify it anyway. Handcannons were the only ones that threw me off as making no sense mechanically. Everything else was fine. Edit: I'll just sum it up to all guns in this game firing energy. Look at the new scout rifle models, the clip is replaced with what looks like a freaking CO2 cartridge in a paintball gun. And it connects TO THE HANDLE.