This one has some spoilers so I dont wanna give anything away, and there is not a whole to explain but this gun can easily easily be missed. All you need to do is reach the rank of "Sentinel" within the Brotherhood of Steel" go and talk to "Proctor Teagan" on the Prydwen and he will be able to sell you the gun, this is probably the ugliest gun in the game or one of them but its nice to have if youre a collector much like myself. The gun also costs around 1k caps.

PLasma Rifle , does double damage when enemy is at full health

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