The FAMAS rifle was originally adopted for use with 55 grain ammunition, with a 1:12 inch rifling twist rate and, of course, a proprietary 25-round magazine. This was the F1 pattern. Further development of the rifle with an eye toward international sale led to the G1 pattern, with a 1:9 inch twist suited to the Belgian SS109 62 grain projectile adopted by NATO, as well as the use of NATO-standard magazines (specifically FNC magazines). While the French Army was quite satisfied with its F1 rifles, the French Navy decided to modernize in the early 1990s.
The commercial G1 rifle had been economized by removing many of the extra features like bipod legs and grenade launching hardware, and the Navy wanted those elements reinstated. GIAt did that, and the result was the FAMAS G2. A total of 10,000 were manufactured for the French Navy, and they are the last FAMAS rifles to be produced before the St Etienne production facility was shut down and GIAT left the small arms business entirely.
Thanks to the French Ministry of the Interior for allowing me access to this very scarce rifle to show you!