Rooster Cogburn (1975)
Rooster Cogburn is the 1975 sequel to the original 1969 western True Grit. John Wayne returns to the role of Deputy US Marshal Reuben J. "Rooster" Cogburn, who is accompanied by a woman (Katharine Hepburn) whose father was killed by outlaws as they both try to recover a shipment of nitroglycerin. The film also goes by the alternate title Rooster Cogburn (... and the Lady).
The following weapons were used in the film Rooster Cogburn (1975):
Colt Single Action Army
As in True Grit (1969), Deputy US Marshal Reuben J. "Rooster" Cogburn (John Wayne) carries a Single Action Army revolver with a 4 3/4 inch barrel and ivory grips. He is seen using the revolver notably in a shootout with a gang of outlaws in a hideout at the beginning of the film.
(The following is from the True Grit)' page.
Although Wayne owned many Colt Single Action Army revolvers, this gun, serial number 309795, was the only one of his personal Colt Single Action Army revolvers he used in his films. This gun did most of the shooting in his films. Even though it was always billed as a .45 Colt, it was chambered for .44-40 WCF in reality. The interesting part is, this gun (serial no. 309795) didn't leave the factory as a regular Colt Single Action Army. It was originally a Colt Single Action Army "Bisley Model" with a 5.5 inch "Artillery" barrel, and was chambered in .45 Long Colt. It was later rebuilt to resemble an average Colt Single Action Army with a "Civilian"/"Quickdraw" Model barrel and was converted to fire .44-40 WCF cartridges. All three of these guns were fitted with ivory-style grips (manufactured by Maurice D. Scarlac out of a material he developed called Catalin). Wayne like them so much that he took these grips home and personally "tea-stained" them to give them that desirable "mellow aged ivory" look. Two sets of these grips were made for Wayne (the second set being a spair just in case if the first set broke). These grips all had three finger grooves in the left-hand side of the grips for Wayne middle, ring, and "little" fingers of Wayne's right hand for as they wrapped around the revolvers grip frame. The grooves can be clearly seen in the climactic gunfight between Rooster and "Lucky" Ned Pepper and his gang when Rooster has the gun tucked in his waist band.
This Colt revolver was used by Wayne for the remainder of his film career ,almost exclusively, from The War Wagon (1967) to Rooster Cogburn (1975). the notable exceptions would be McQ, Brannigan and The Shootist.
For more information about John Wayne's SAA revolvers, go to the following link: 
Winchester 1892 "Saddle Ring Carbine"
Rooster once again carries the Winchester 1892 "Saddle Ring Carbine" with a large lever loop chambered in .44-40 as his rifle of choice throughout the film.
Winchester Model 1894
Allen & Thurber Pepperbox
Rooster keeps Allen & Thurber Pepperbox, that he describes as a ".22 pepperbox" as a backup to his SAA, which he gives to Wolf (Richard Romancito) to protect himself and Miss Goodnight. This may be a .36 cal instead of a .22.
Colt 1874 Gatling Gun
Both Eula and Rooster are seen using a captured Colt 1874 Gatling Gun mounted on a tripod. Eula uses it to pin down some outlaws and Rooster uses it notably on the raft while traveling down river with the nitroglycerin. The rate of fire heard from the Gatling gun make it sound more like a Browning M1919 machine gun.