Actually, the gov't and the stupid EPA have shut down all but 1 lead smelter here in the USA, so yeah, we kinda are having a metal shortage. But I wouldn't say that is the primary reason why bullets aren't available.
The primary reason, is because nutjobs keep going on shooting rampages. And the liberals cry about it and how guns are so bad and terrible. Then the gov't tries to take our guns, ammo, and mags away. So people go out and hoard everything they can as soon as it become available to them. So there isn't anything left on the shelves for folks like us, who already have a stash, but want to be able to leisurely pick up a box of bullets or 2 here and there as we need them. Now the name of the game is hoard everything you can, and it screws everybody...