Payback is a 1999 action film starring Mel Gibson as a thief who is double-crossed by his partner and his attempt to get the money owed him back. Unsatisfied with the original tone of the film as well as the ending, Gibson decided to reshoot several sequences and add several characters to the film before its release in 1999. In 2006, director Brian Helgeland was allowed to go back and restore his original vision for the film. It was released on DVD as "Payback Straight Up: The Director's Cut". Most of the screencaps for this page are from the Director's Cut.
Porter (Mel Gibson) uses a blued Smith & Wesson Model 29 4" with S&W factory combat grips for the majority of the film after buying it in a pawn shop. It is not a Smith & Wesson Model 27 as previously mentioned, as the diameter of the muzzle and cylinder chambers is clearly too large to be .357 Magnum. Also the barrel on the Model 27 has a slight taper while the barrel on the M29 is a heavy "bull" barrel. In addition the forcing cone on the Model 27 is visible and the cylinder is shorter on the Model 27. The cylinder on the Model 29 fills the frame. Like the one used in the movie.In addition the Model 27 has very fine checkering on the top strap. Observe the stills that show the top strap on the revolver being used by Mel Gibson. It's smooth which is another feature of the Model 29.See the discussion page for comparisons. There are clearly two different S&W revolvers used. One is a S&W model 29 and the other is a S&W model 27/28. In the pictures of Porter firing the revolver and the Beretta and again pointing at Lucy Liu, you can clearly see the barrel taper of a 27/28. While the gun may switch between the 29 and 27/28 in the same scene, there is definitely a 27/28 used.
Val Resnick (Gregg Henry) carries a Beretta 92FS pistol as his main sidearm, which Porter (Mel Gibson) takes from him and uses for the rest of the film.
Pearl (Lucy Liu) carries a blued Walther PPK with pearl grips (possibly in relation with her name) as her sidearm.
SIG-Sauer P220
The Triad van driver is seen firing a SIG-Sauer P220 through the floor of the van at Porter (Mel Gibson). Earlier in the film Porter is seen taking a SIG P220 from one of Carter's (William Devane) guards after knocking him out with a roll of pennies and then using it to kill him. They are noted as the P220 model by their lack of double stack bulges on the frame, and their .45-sized muzzle diameters.
M3 "Grease Gun"
When Porter (Mel Gibson) is attacked by the Triad gang members, two of them are seen firing M3 "Grease Guns". They clearly have external charging handles, helping to identify them as older M3s, not M3A1s.
Glock 17
One of the Triad gang members is seen using a 2nd Generation Glock 17 to shoot at Porter (Mel Gibson) in the taxi cab. Later Porter is seen disposing of two Glock 17s after killing two thugs in the restroom.
The two Glocks Porter takes from the restroom thugs appear to be first generation models due to their lack of ridges in the grips.
Radioman (Kwame Amoaku) tries to save Arthur Stegman (David Paymer) with a sawed-off Remington 870 shotgun before being mowed down by the Triads. Based on the sling swivel on the pistol grip, it is assumed this gun was professional sawed down by a film armorer.
One of Carter's (William Devane) bodyguards is seen armed with a Heckler & Koch P7M8 before Porter (Mel Gibson) knocks him out with a roll of pennies. An Outfit member is seen firing one at Porter during the final firefight as well.
I am pretty sure this is a HK P7 and not a M8. Look at the first pic. The gun lacks the mag release latches on the trigger guard, and the guard itself is much smaller like the P7 over the M8, biggest give away is the gun shown lacks the heat shield in the trigger guard.
Ruger Mark II
An Outfit thug at the train station opens his lunchbox to reveal Ruger Mark II pistol with an integral suppressor.
Walther P38
Inside the pawn shop, a Walther P38 is seen hanging on the pistol rack, along with several unknown revolvers.