Fallout 4 How to find the GAMMA GUN (Gamma Gun Location)
One of the places where you can get a Gamma Gun without having to do a quest or crafting is on the very right of the map. Look for the “Kingsport Lighthouse”. There you will find some Child of Atom Preachers, which can be really tough enemies if you haven’t really leveled your character yet.
In the video i was lvl 7 and didn’t have the slightest chance with normal guns. On the road leading up to the lighthouse are some mines that you can pick up and use against the preachers.
Since they all have the Gamma Gun equipped, you can simply kill one, grab the gun and get out again. If you have a stronger character you could take them all out and stock up on gamma rounds.