try brickarms brickforge and little armoury
yes, but they're are harder to get, because you have to buy them online, or have them custom made, like Brickarms does with guns and weapons
A Machine
They either buy it seperately or from a Lego set.
LEGO and brickarms are not connected, but brickarms makes their own LEGO guns that are compatible with LEGO especially the minifigures.
Only Space Rangers have guns.
If you go to www.brickarms.com they have increbidle Lego guns!(do not be discouraged by the prices($2-25 cents), they are AWSOME!!! Another website is www.brickforge.com, which makes guns as well as other minifig acessories.
You will have to hunt around for custom army Legos as Lego themselves do not make modern day warfare sets. You should be able to find Lego army men, guns and sets (or just instructions) for vehicles like tanks at websites like Ebay and Amazon.
guns for the clone troopers
Custom made
Probably, because the movies have stopped coming out, all the Lego will turn slowly to Clone Wars things, as more Clone Wars episodes and movies come out. Oh, and guns are making the transition from megaphone-shaped things with a coloured bulb at the end to complex things that look more like they did in the movies.
guns