I took a look around the forum to figure out where I would even put this topic, and I wasn't exactly positive, so if I messed up, I apologize. Well, I'm new to firearms. My father and mother both didn't approve of them, so I never grew up around them. I recently enlisted into the US Navy, and that's when I decided I'd want to learn about firearms. I don't know a thing though, I have a few ideas here and there, but I'm not positive on anything. So, what I was wondering was, if someone could help me out and give me some info on the following: Bullet Size - What is caliber and mm? What is a cartridge made of? - What is the physics of the bullet actually going off, what happens with the firing rod strikes the primer? What kind of gun should I get? Where can I use it? What is gas operated? How does a typical weapon actually work? - The mechanics of it. Any more information anyone else can throw at me would be nice, when I get done with RTC and get my orders from my detailer, I'm joining the NRA.