The FN FAL reference article from the English Wikipedia on 24-Apr-2004
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FN FAL

The Fusil Automatique Leger, or Light Automatic Rifle (LAR), also known as the "right arm of the free world," the FAL rifle was the NATO equivalent to the AK-47, in terms of the sheer number of countries that adopted it. Unlike the AK-47, it utilized a full-power rifle cartridge (the 7.62x51mm NATO standard round). The FAL was made by Fabrique Nationale de Herstal and under licence in a number of countries. Including The UK, South Africa (designated R1) and India and Argentina.

The British adopted the FAL and manufactured it based on an imperial measurement pattern with minor amendments including folding cocking handle, prong shaped flash eliminator, folding rear sight, sand removing cuts in the slide and beefed up magazine catch and were semi-automatic only. Most parts on the British version are not interchangable with those built on a metric pattern. The British version was designated L1A1 and know in service as the 'SLR' (Self Loading Rifle). It was replaced in the early 80s by the SA80.

The FAL is an automatic rifle, and operates by means of a gas-operated action. The gas system is driven by a short-stroke piston, and the locking mechanism is what is known as a tilting breech block, as to lock, it hinges down into a solid shoulder of metal in the receiver. Magazine capacity ranges from 5-30, with most magazines being 20 rounds.

More information, including pictures: http://world.guns.ru/assault/as24f-e.htm