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 Mk III in a few scenes at Laughlin's (Dub Taylor) hotel.
Jack Benyon (Ben Johnson) has a Smith & Wesson Model 36 out on his table when Doc brings him the bank robbery money to count. He grabs it just before he is shot by Carol.
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).
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.
Browning Hi-Power
Max, one of the cowboys during the final shootout, carries a Browning Hi-Power.
unidentified revolvers
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.
Smith & Wesson M76
One of the cowboys during the hotel shootout uses a 9 mm Smith & Wesson M76 submachine gun.