You don't open the small barrel of explosives. Once you have the Cannon Starter Kit (fuses) from the top of the mast, push the barrel into the water below, and swim it out under the Golden Tooth. Shooting the barrel with the cannon at the left side will explode it, shaking loose the Golden Tooth and revealing the map piece.
Mexican Golden Barrel Cactus, Echinocactus grusonii, Arizona
The small barrel of explosives is on the mast at the Pirate Outpost. Climb higher and also get the Cannon Starter Kit (fuses). Push the barrel down into the water and under the giant golden tooth. Fire the cannon at the left side to hit the barrel and blast loose the golden tooth : the map piece is under it.
There are several of them, such as the golden barrel cactus (Echinocactus grusonii).
Above the Cannonry, at the top of the mast, is a "cannon starter kit" (fuses), which will fire any of the four cannons on the outpost. Just below is a small barrel of explosives. Push the barrel left, off the mast, and into the water below. Swim it over to directly under the Golden Tooth on the rock skull. Go left and fire the cannon there. Hitting the barrel will shake loose the Golden Tooth and reveal the hidden map piece.
A size of a head of a big child or a head of a small man...
It would help if you could tell me which "golden Marlin" model you have? Also condition, features, etc. Marlin made several guns with "Golden" on the barrel, but there should also be a model designation somewhere.
Just below the Cannon Starter (top of the mast at the Pirate Outpost) is a small barrel of explosives. Push it off to the left, and down into the water. Place the barrel under the golden tooth, then fire the cannon on the left side. The explosion will shake loose the golden tooth and reveal the map piece.
If it is not marked on the barrel, take it to a gun smith for a chamber cast.
When at the port, go left and through the golden gate, keep moving left... Build the golden piece just in front of the water, head NE and get one of the barrels, ride the barrel to the orange platform, behind the golden object, keep running with the barrel to make the bridge go up. Go back to the other barrel, ride it across the bridge, put it in the orange platform and keep running, when the door opens: go in and jump on the two ropes close to the blinds, go upstairs, and you'll find mix and match!!
The map piece is not in the existing cavity in the giant skull, but under the Golden Tooth. Go to the top of the mast at the Pirate Outpost, and get the cannon starter pack (fuses). Then push the little barrel of explosives off the mast into the water, and place it under the giant golden tooth. Then go to the cannon on the left side. Click on it to fire. If it hits the barrel, it explodes, and the Golden Tooth will fall out, revealing the map piece. (see related question)
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