If you're playing Cyberpunk 2077 and have come across Johnny Silverhand's gun, The Malorian Arms 3516, you may have noticed that there is a "!" symbol next to it. This means that the gun is locked and cannot be stashed, leaving you wondering which quest it is related to.
One possible explanation is that the gun is locked due to a quest requirement. You may have to complete a specific quest to unlock the gun for stashing. This could mean progressing further in the game or completing certain side quests to unlock the quest that requires the gun. It is also possible that the quest is related to Johnny Silverhand's storyline, and you may have to complete his story quests to unlock the gun.
Another possibility is that the gun is a rare or unique weapon, and it cannot be stashed due to its rarity or uniqueness. In this case, you may have to keep the gun in your inventory until you find a vendor who is willing to buy it or trade it for another weapon. It is also possible that the gun has a special ability or feature that makes it valuable, and you may have to keep it for its unique properties.
If neither of these solutions work, it is possible that the gun is locked due to a bug or glitch in the game. In this case, you may have to try reloading the game or restarting your console to fix the issue. Alternatively, you can report the bug to the game developers to get it fixed.
In conclusion, there could be several reasons why Johnny Silverhand's gun, The Malorian Arms 3516, is locked and cannot be stashed. You may have to complete a specific quest, keep the gun in your inventory, or report a bug to fix the issue.