The Universal Carbine, officially known as the FN Automatic Carbine, was a British-Belgian prototype assault rifle that was produced by RSAF Enfield. It was the predecessor of the highly successful FN FAL battle rifle.
The FN Automatic Carbine was developed in the mid-1940s by Belgian engineers from FN Herstal who had fled to Britain during World War II. Design work was completed at the Royal Small Arms Factory in Enfield and the original models were built for the German 7.92×33mm Kurz cartridge. The gun was produced in two versions; a standard configuration designated as the No.1 model and a bullpup configuration designated as the No.2.
In February 1948 the Automatic Carbine was taken to Belgium for testing at Zutendael. It was decided to switch the chambering from 7.92mm Kurz to the newly-developed .280 British cartridge (known in Belgium as 7mm Short), which was preferred by FN. Further testing of the new .280 model was undertaken in 1950 at Enfield and significant changes to the No.1 design were made in response to feedback from these tests, including adjustments to the rear sight and stock, repositioning of the fire selector, and the relocation of the cocking handle to the left side of the receiver. Minor improvements, including the ability to take rifle grenades and a new bipod attachment, were also made.
While the No.1 model underwent substantial improvement, the No.2 was abandoned after it was found to be less reliable and more uncomfortable to shoot.
The improved FN Automatic Carbine in .280 caliber was under consideration for adoption in Britain, but preference was given to Enfield's EM-2 project, which was briefly adopted in 1951. However, British authorities failed to persuade the United States of the advantages of the new cartridge and were soon pressured into adopting 7.62×51mm so as to conform with new NATO standards.
With the .280 cartridge now abandoned, FN could no longer market the Automatic Carbine in its current state and decided to redevelop the gun for 7.62×51mm NATO. Continued work over the next few years resulted in the design of the FN FAL.