So, as a relative newcomer to Rollplay, I was listening to the Swan Song MP3s, and I reached ep 38. Specifically the scene where Alpharius shoots his mag pistol. Hate to break it to you @iNcontroLTV , but railguns do make noise. So much so they sound like an actual gunshot. Basically because the gunshot is actually caused by the bullet reaching sonic speeds in the barrel, shortly followed by the bang caused by pressurized gases escaping the barrel at the same speed as the bullet.
Thankfully, they are conducting railgun tests so there is video evidence to support this.
It just struck me as funny listening to the whole thing because @AdamKoebel was right when he first described it as a gunshot.