Rockstar has been constantly adding tons of new content to Grand Theft Auto Online including stuff like accessories such as new outfits, shoes and bags to help your character stand apart from the crowd.
This guide will tell you how to get the Railgun in the game.
How To Get The Railgun

The Railgun is exclusively available for those players who are returning from older consoles like Xbox 360 and Playstation 3 after completing the mission Minor Turbulence.

Use a boat to reach there and then dive into the water. You will find the Railgun lying in one of the corners.

That’s it, now enjoy blasting your enemies with this powerful gun!
