I've never seen bullet weights that heavy, unfortunately. The heaviest I've ever seen in freshwater sinkers is 1 oz, which considering that most lakes don't have the heavy current of saltwater is pretty much as heavy as you need. The good news is that banana sinkers can be rigged as sliders as well. Instead of tying the line directly to the sinker, run it through the swivel rings at both ends and tie it to the hook. A large swivel tied to the main line a few feet up should keep it reasonably close to the hook when casting.