The main sidearm of bank robber Carter 'Doc' McCoy (Steve McQueen) is a Colt Government. An M1911A1 also appears in the hand of his wife Carol (Ali MacGraw) when she shoots Benyon and during the hotel shootout. A Star Model B is substituted for the Colt in scenes that require the pistol to be fired, as the Colt was not reliable with blanks.
In a continuity mistake of the movie, we see that Rudy's Colt Python is replaced for a Colt Trooper in a few scenes at Laughlin's (Dub Taylor) hotel.
Browning Hi-Power
Max, one of the cowboys during the final shootout, carries a Browning Hi-Power.
Ruger Mark I Standard
When McCoy is in the gun shop, we can see briefly several guns, including a Ruger Mk I Standard, hanging on the wall (I think there is also a Colt Woodsman, but I am not really sure).
Smith & Wesson Model 10
Frank Jackson (Bo Hopkins) carries a S&W Model 10 during the bank robbery, which he uses to shoot the bank guard.
The bank guard carries a .38 revolver, as McCoy tells his bank robbery team.
Cully (Roy Jenson) and the other cowboys all carry revolvers during the final shootout in the hotel.
unidentified snubnose revolver
Jack Benyon (Ben Johnson) has a snubnose revolver out on his table when Doc brings him the bank robbery money to count. He grabs it just before he is shot by Carol.
High Standard 8111
McCoy goes into a gun shop to buy a 12-gauge pump shotgun and is given this rarely-seen High Standard 8111 by the shopkeeper.
Smith & Wesson M76
One of the cowboys during the hotel shootout uses a 9 mm Smith & Wesson M76 submachine gun.