Eli (Denzel Washington) carries a weathered Heckler & Koch HK45 pistol (an LEM variant as noted by the bobbed hammer and lack of external safety). Even though the pistol had just been out a year when the film was made, the filmmakers wanted it to look like an antique vintage firearm (as this film takes place in the future). The brand new HK45 was sanded and worn down to look very old for the film. In true movie fashion, Eli fires about twice as many rounds as the pistol can hold before reloading. The actual pistol is currently on display at the National Firearms Museum located at the NRA headquarters in Fairfax, VA.
Remington 870 "Witness Protection" Short Shotgun
Eli (Denzel Washington) carries a short barreled Remington 870 "Witness Protection" shotgun, with various weathering and a heavily taped handle.
A Colt Police Positive is seen at the beginning of the film, lying on the ground, unloaded, in the middle of the woods. It is never held or fired, however.
Another Remington 870 with mag tube extension and saddle shell holder is used by one of Carnegie's men. He is seen most notably at the end loading his shell holder as anarchy breaks out at Carnegie's bar near the end of the film. Other men are seen with different Remington 870's.
AK-47
One of Carnegie's thugs carries an AK-47 (exact variant unknown at this time).
Carnegie's thugs spread out to find and kill Eli. They carry some bolt action rifles of unknown make and model.
M1903 in a Mannlicher Schönauer Carbine stock
When Eli is walking through the town the camera pans on a man on a roof with a bolt action rifle. This rifle is a sporterized Springfield M1903 Rifle with a Lyman peep sight and fitted into a Mannlicher Schönauer Carbine (Stutzen) stock. The military stock had been replaced, as well as the sights, and likely the parkerized finish was replaced with a blued finish. This was common practice at a time when surplus military rifles were cheaper than sporting rifles. It is the same prop featured in the film A Boy and His Dog, noting the heavy stylistic and atmospheric homage already paid, as well as featuring a poster of the movie.
Gatling Gun
At one point, Carnegie's men use a hand-cranked Gatling Gun on the house Eli is holed up in.