How a Gun Works..?

Question

Ok now I get how a basic gun works w/ the pistons firing it off, and the force from the bullet winding the bolt back and all of that. But how do bigger/mounted guns work? Like anything bigger than a .50 Cal (I'll just use the 50 as an example).

I know that the trigger lets the bolt loose, it pulls the bullet down through the Chambering Ramp, the forward force makes the piston slide forward and hits the bullets primer; shooting the bullet forward. Then the force from the bullet brings back the bolt and the whole process restarts. So I understand the actual firing. But;

-How does the bullet get to the Cartridge Guide?
-How does the shell get out of the gun? (You always see them coming out onto the ground, what makes them come out of the gun)
-And what exactly does the Operating Rod do? I cant really see a point but it probably has a major role

So three questions; 10 points for 3 answers. Thanks for your time.

Answer 1

Look:

www.floridagunworks.com

http://www.americanselfdefense.com/articles.asp

http://www.americanselfdefense.com/gunfacts3.0.pdf

http://www.thegunworks.com/GunIndex.cfm?next=link#

http://www.egw-guns.com/ (very good / many photos)

Answer 2

Make sure your mum ties up your shoes real nice before she lets you go out tomorrow morning, okay.