1943 Union Switch & Signal
SN 1,082,358

Union Switch & Signal company of Swissvale Pennsylvania, primarily made railroad signaling equipment but received a contract on May 5, 1942 for the manufacture of 200,000 M1911A1 pistols.  The first pistols were accepted by Ordnance inspectors in January 1943, but the company received word that their contract would be canceled, due to a severe drop in requirements for the pistol.  Within a month U.S.&S. had signed a contract to supply carbine parts. On March 8, 1943 the company was officially notified that their contract had been cut back from 200,000 pistols to 30,000 pistols.  However on June 26th, when the contract was nearly complete, and many of the workers had been transferred to Carbine operations, the company received a letter of intent to purchase an additional 25,000 pistols.  The last of the pistols was shipped on November 27, 1943.  55,000 Union Switch and Signal pistols were delivered serial numbered from 1041405 to 1096404 with peak production reaching 650 pistols a day.   

U.S.&S. pistols are the second rarest of the M1911A1s, only the Singer is rarer.  None of the Union Switch & Signal 1911A1s have the crossed cannons ordnance stamp even thought the practice was standardized in late 1942. Also most of the early pistols up through about serial 1060100 received no “P” proof on the slide and frame.  From about 1060100 to about 1082000, the “P” proof was applied, but at the Left edge of the slide where the curved part meets the flat.  This was due to a poorly drawn ordnance drawing showing the placement of the proof.  From about 1082000 to the end of production, the “P” was placed in its normal location on the top of the slide (center in front of rear sight).  When the "P" proof mark is found it will be on both the slide and receiver and be of the same size. Notice the "P" proof stamp is smaller then Colts but still an uppercase letter. This pistol has the type 3 proof configuration, with the P in the middle of the slide, and is in the expected serial number range.

The number of different machining operations performed by US&S on the parts for the pistol, was 600. These required the services of 658 different machines; 421 types of cutting and drilling tools; 239 different fixtures, and 447 different gages. While the Government owned the machines, gages and fixtures, US&S provided its own perishable tools. The receiver for each pistol underwent 106 individual operations, during which some for fifths of its weight was machined from the original forging.

It is reported that Union Switch & Signal produced high quality pistols and did not experience the extreme production problems that Remington Rand and Ithaca had. The ordinance department reported the Union Switch & Signal pistols had a superior finish and consistently rated high in the interchangeability tests. Reference Charles Clawsons “Colt .45 Service pistols”. Click on images for larger one.


Right profile

Legend, Trigger, and Slide stop

Serial Number

Rear sight, hammer, and Proof mark


Sight and hammer view

Thumb and grip safety

Grip safety and pins

Mainspring housing

  • Barrel is made by High Standard

  • Front Sight is serrated

  • Rear sight is square notch

  • Trigger is short, stamped, and many where blued

  • Safety and slide lock where checkered

  • RCD is the Inspectors mark, Lt. Col. Robert C. Downie
    (Located below slide lock)

From the T. Moore collection
Images copyright Ty Moore and Karl Karash

Hammer and rear view

Grip safety

Ejection port

Front sight