The Rocket Launcher is not just like any other gun in Ghost Recon Breakpoint. If you want to use it you’ll need to equip it first. This weapon is a reward in the game after reaching Erewhon for the first time and the place you equip is actually in your loadout.
It’s different than using your standard weapons
If you open your inventory screen and head to the backpack icon for loadout, you’ll see a backpack with items at the bottom of the screen on the left hand side. There are multiple boxes that you can interact with that allow you to change between items that you want to equip. To use the Rocket Launcher, you’ll need to equip it in one of these slots.
Once you have the Rocket Launcher equipped to your item wheel you can use it just like any other item. Press the RB button to open the wheel and then highlight the Rocket Launcher. You will now see the rocket launcher as your active item in the left hand side of the UI. You can then bring up the rocket launcher by pressing the LB button
To use the Rocket Launcher one equipped you will have to hold the LB button while you press the Right Trigger to fire. If you release the LB button before firing you will lower the rocket launcher instead of firing.