one thousand is to heavy. Consider this, it weights nothing to you, but 1000 pounds in reality. You swing it with all your strenght, and because its nothing to you, you can put far more force into it than would normally be possible. Now think, anything it hits will explode into a bloody mist, with some chunks of bone and sinew, maybe a bit of brain. if someone found enough body parts to try regrow him they'd be lucky. And because it weights nothing to you, you can swing it super fast to, making it very hard to dodge.
So heres how we'll fix this, cut the weight to 250, and make it so the weapon weights 10lbs to you. that will atleast stop you from swinging it uber fast and hard.