Choose the correct entrance
The Rifle is in the upper part of the Ancient Armor cave network, reached from Grotto D at the eastern large lake. Do not apply this route from the island’s other Ancient Armor entrance.
Bring the Rebreather, air tanks, light and combat supplies. Find the rock opening beside the lake east of the central snowy mountain range.
Dive and follow the right wall
- Enter and descend towards the low water area at the back.
- Swim through the long underwater tunnel with the Rebreather.
- Surface near a body, then continue along the right-hand wall.
- Look towards the lit area and another dead body for the Rifle. Rifle ammunition is described nearby on the ground.
- Collect the weapon and confirm Rifle in your inventory.
If the route does not match
Recheck the entrance first. Confusing the two sides of the cave network is the major failure point described by these references. This guide gives relative landmarks rather than verified current-build coordinates or a continuous recent recording of every branch.