Sacred Haven of Debauchery

Desert Eagle isn't great, pistols are generally bad, even the Gauss Rifle.

I wouldn't say that. In the end, I managed to get 5 shots from the Gauss Rifle per turn, just slightly less total damage than the Gauss Cannon, but with better damage distribution, which sometimes allowed me to kill three Enclave soldiers per turn, compared to two with the Gauss Cannon.