The CETME/G3 uses the delayed roller blowback system which was spawned by German engineers right at the end of WW2. It was destined to potentially be the successor to the StG44, and a few prototypes were made, but it never got into production. The same German engineers landed up in Spain post war and their efforts manifested into the CETME - a 308 delayed roller blowback battle rifle. Ultimately Germany adopted the exact same rifle with minor modifications in the guise of the G3.
We previously tested the FAL here: https://www.full30.com/video/583b9d4ac5e2d4913d067dc84be6b6df
How will the G3 do in the InRange mud test? Let us find out...