The FAMAS was one of the first mass-produced bullpup rifles, and as a forerunner in the area, it shows a number of interesting features, both good and bad.
The FAMAS spent 9 years in development, beginning in the late 1960s and finally being adopted as the standard French Army service rifle in 1978 (replacing the MAT-49 SMG and the MAS 49/56 rifle). During this time, prototypes and 7 progressive variants were made (A1-A7) before finally settling on the F1 model for adoption.
Mechanically, the FAMAS works much like a San Cristobal carbine or AA-52 machine gun, using the lever-delayed blowback system developed originally by Pál Király. The bolt is not rigidly locked when fired, and immediately begins to move backwards. An “H” shaped accelerator lever is connected in the center to the bolt itself, with the bottom legs firmly against recesses in the receiver below, and the upper legs pushing on the bolt carrier. The accelerator cannot move back past the receiver lugs until it has rotated about 45 degrees, and its upper legs are longer than the lower ones. This forces the bolt carrier to move backwards much farther and fasted then the bolt itself can move. The time required for the bolt carrier to move far enough to release the accelerator lever and allow the bolt to move backwards is long enough to allow pressure to drop to a safe level in the chamber, and the built up momentum of the bolt carrier is used to cycle the action and load a new cartridge. A fluted chamber is used to facilitate extraction.
This system is fairly simple and negates the need for a gas system, but it does have limitations. It is really at the limits of a safe mechanism for a high-pressure cartridge like the 5.56x45mm, and does not have much tolerance for variation in chamber and barrel pressure. The initial F1 variant of the rifle adopted by the French Army was designed around the 55gr M193 cartridge, including a 1:12″ twist that is not compatible with the now-popular heavier 62gr and 77gr bullets. We have also been told (although not found confirmation) that the locking system itself is not overly reliable with heavy bullets, due to the difference pressure curve created by those rounds. The newer G2 and export versions of the rifle are built to run fine with heavier rounds (mainly SS109 62 grain), but the vast majority of Army rifles in use are still original F1 versions, which will eventually be replaced with a completely different rifle (the H&K 416, we understand) rather than reworking them for the new standards.
In addition, France had removed its military forces from the NATO union in the late 1960s, and the FAMAS was not designed around NATO standards, although it did use the same ammunition. Magazines were straight 25-rounders, not interchangeable with STANAG M16 mags (although this was also changed in the 1990s G2 version).
Unlike many other bullpup rifles, the FAMAS was not built with optics mounting in mind – it is equipped with iron sights inside the top of its carry handle. These are enough to get the job done, but not particularly outstanding. It is worth noting, though, that both the front and rear sights are actually mounted to the barrel and receiver, and the carry handle mounts around them. This does improve accuracy, as slop in the carry handle mounting will not translate into movement of the sights.
The fire selection leaves something be desired. The rifle has a safety lever inside the trigger guard, which rotated from left to right. The right (marked “1″) is for semiauto fire, the middle position (which physically blocks access to the trigger) is for safe, and the left (marked “R” for “refale”, or burst) is for automatic fire. That automatic fire can be either full-auto or a 3-round burst, as dictated by a second selector located under the buttstock. That one has markings of “0″ (for unlimited full auto) and “3″ for 3-round burst. Today burst firing has pretty much been determined to be undesirable, but it was still though to be a neat idea when the FAMAS was being designed.
Most notable for an early-adoption bullpup, the FAMAS can be fairly easily changed from left-handed to right-handed use. The charging handle is entirely ambidextrous, located atop the receiver inside the carry handle. The bolt is made with cutouts for the extractor to mount on either the left or right side, and the receiver has ejection posts in both sides. The desired ejection port is left open and a detachable cheekpiece is mounted over the other one, and the extractor is fitted to the ejection side of the bolt. To switch the rifle’s ejection side, the extractor and cheekpiece are simply moved to the opposite sides. This is not practical to do in combat, so the rifle can’t effectively be juggled from shoulder to shoulder, but it does allow lefty shooters to use the rifle without handicap (and without needing to have any lefty-specific guns or parts).
One other feature to note – the lever in front of the charging handle is actually a grenade launching sight. The FAMAS was designed to use 22mm rifle grenades that slip over the barrel. To aim them, the rifle is laid on its side, and that lever is flipped out to a detent setting based on the desired range of the grenade. The firer then sights down along that lever at the intended target.
We have two manuals available for the FAMAS, one in French and one in English (both describing the original F1 variant):
FAMAS F1 manual (English)
FAMAS F1 manual (French)
You can also see the full gallery of photos (or download the whole batch here as a zip archive):