Where can I find this monstrosity?

I need a powerful silenced killer. I have the silencer for it, and just a few rounds of ammo, but no gun. I read on the wiki that it can be found at Bloodborne Cave. Where is that?

Also in general, what weapons can have silencers attached? So far, I have them on my 9mm, 10mm, and Vermint Rifle.

I'm guessing this is a New Vegas topic, so moving ...

one of the khans had it in red canyon.

It is East of the Brotherhood of Steel Safehouse. You can find that by going to Raul's Shack and heading Southeast.

You could also go to Nellis Air Force Base and head South to the train tunnel. When you come out the other end of that, you'll be halfway between Raul's Shack and the Brotherhood of Steel Safehouse.

I found it in the old ladys junk yard in side her shack just lying on the floor. Unbreackable combat armor? There's a reclcharable rifle and pistol in the silver traders in freeside, just kill them all and steal all there s#€t lol