Firearms
come in all shapes and sizes and are manufactured
for a variety of purposes (hunting, recreation,
competition, military use). Price
can be anywhere from $100 - thousands of dollars.
Categories of firearms include: Pistols, Rifles,
Shotguns, and Muzzle-loaders.
Pistols
are hand fired
firearms (handguns). They
can be semiautomatic, single shot, revolver, or
fully
automatic in nature.

Semi automatic Kimber 1911 handgun.
Cartridges fed by a spring loaded magazine. http://t0.gstatic.com/images?q=tbn:
ANd9GcRsDUIrZhwmf8S2CAmC3BR4P4Wr5GliPAoXQTSrgxPoogtIIhC-

44.mag
revolver handgun. Cartridges are fed into chamber by a
revolving cylinder. http://t2.gstatic.com/images?q=tbn:ANd9GcQWRuMUksbxJKibG99zxQL
W6U0jwKYv
1LBL91zQ6XhLeiLvEuW-iQ
Rifles are shoulder fired firearms. They
can also be single shot, semiautomatic, or fully
automatic in nature.

Modern
day hunting rifle. Cartridges fed in the chamber by a
bolt. http://www.hatchergun.com/images/DH_Rem_280-1.JPG
Shotguns
are a form of a rifle designed to shoot multiple
projectiles in one shot (Slugs and other specialized
ammo are an exception)

A
typical modern bird hunting shotgun.
http://images.wikia.com/fallout/images/3/3d/HuntingShotgun.png