Bah! Sneaking is for pansies!
No weapon can one shot rawr, But Mercy can make very quick work of any Deathclaw or Cazadore.
If they get into Melee range, Your not doing it right!
I don't remember VATS in FO1........
I think I killed Rawr in one shot with the YCS/186 with Max Charge ammo and appropriate perks. But Esther with Big kid ammo and appropriate ammo should make short work of him. He would die from a heart attack before the mini-nuke exploded.
At the original post (get your abbreviations out of here
) I would exchange both weapons. First I would grab the Survivalist's rifle. It uses the easily obtainable 12.7mm, has pretty quick reload time, The normal damages are about the same, but with perks the Survivalist's Rifle's normal shots can almost match the Gobi Rifle's critical shots. Plus the clip size is biggerm and it shoots faster. The only thing that the Gobi beats it on is spread and that is due to it being a sniper rifle, the Survivalist's rifle is still good medium range.
And for the closer range variety of targets I would switch your SMG with the riot shotgun, much more diverse ammo types, even to kill robots if you have GRA, and the ability to set things ablaze. It also has much much higher damage than the 12.7mm SMG if used properly, and the ability of semi-auto makes it very good even against fast enemies. It's large clip for a shotgun also keeps you safer than other shotguns, and due to the ammo being in a drum it reloads quickly too.
Edit: Explosive weapons are arguably the best if used correctly. You just have to have every perk you can get for them. I have also used VATS to kill people in one shot from Mercy that was a considerable distance away. It is always fun to count the seconds while watching the shot fly through the air, then the unexpecting enemy gets it in the face. Also everyone seems to forget about Annabelle, that thing with HE ammo is devastating, and most likely kills limbs in one shot if it doesn't get the enemy.