With a normal sword it uses the pistol I believe. With a heavy? I don't think I tried, as I never bothered with them. Dagger of Romulus beats all. 
Well, yes, you can only throw heavy weapons like the Bearded Axe. Not regular swords, nub
And it's not about effectiveness. It's just really cool to plant a two-handed sword in someones back from a few yards away
My favorite weapons are the spears and halbers, though. Most brutal kills
