The Double-Action Revolver is a hidden weapon which unlocks after completion of the special quest. It was added to the game as part of The Doomsday Heist and became available on December 15, 2017.
As of August 15, 2018, there are 92 weapons in GTA 5 and Online. They are divided into classes and, unlike previous GTA games, the protagonists can carry all the weapons at once, and not only a single weapon of each class. In addition, death or arrest does not lead to the loss of weapons.
In GTA 5 for the first time in GTA games, there were modifications for weapons, which are also available in GTA Online. They can be installed at Ammu-Nation stores.
Pay attention: GTA Online protagonist keeps weapons forever only after buying them. Trophy weapons are kept only until the end of the session.
The Stone Hatchet is a hidden weapon which unlocks after completion of the special quest. It was added to the game as part of the After Hours content update and became available on August 3, 2018.
The Up-n-Atomizer is a hidden weapon in GTA Online which was added to the game as part of the Festive Surprise 2018. It became available for all players who logged in GTA Online on December 25, 2018.