International Movie Firearms database covers guns from Films, TV, games and anime. It’s a Wiki layout, and very easy to search through categories to find what you want.
Obviously we’re most interested in the guns featured in games.
It has a rather large selection of games. From as far back as Doom to as recent as Modern Warfare 2. It unfortunately doesn’t cover made up weapons, so games like Halo are complelty absent from its listings.
The posts on individual games are pretty in-depth, listing the fire arms used with shot of the real life gun, screenshots and information on its use in game, who carriers the gun, what its like for firing, differences to the real life gun etc. Some articles are a little less in-depth, but its built on Wiki, so feel free to build up its database.
It could do with a bit of a clean up, its rather slap dash with just a column of images for most entries. But if your a gun nut, or more interested in the guns you are firing in-game. Then this is the site for you.