The El Caballero grenade launcher is a pretty powerful machine that ignites the world around it. You may have found this weapon while searching around Yara. The game will tell you to search around the F.I. Escudo Steel Plant. Of course, it also doesn’t tell you how to get there.
What makes this grenade launcher great is that it comes pre-equipped with incendiary grenades, the Reload All mod that reloads all your weapons when this weapon is reloaded, and the Nimble Shooter mod that increases your movement speed while aiming. This gun says it is a rank three weapon, but it should really be a rank four.
The image above shows you where the F.I. Escudo Steel Plant is. It is located northeast section of Yara in the Aguas Lindas Region. The steel plant is one of three FND Bases you can discover in the region.
Before you can gain access to the grenade launcher, you will first want to clear out the FND Base. Take out all the enemies in the area to capture it for Libertad. During the process of taking over the base, you should have picked up the Storage Locker Key from one of the guards.
With the key in hand, head to the area in the picture above. It can be found behind the steel plant. The small room off the back of the steel plant can be unlocked using the Storage Locker Key. Open it up to find the chest with the grenade launcher inside.