This isn't a criticism, but the '94 ban failed because it was written by people like you that don't understand guns. It was a silly and stupid way to try to attack the problem.
Your ammunition proposal, just as an example, here are all of the cartridges available in an AR-15 or AR-10:. (see link)
Included are many, many very popular sporting rounds. This is how your side loses this issue. "I can't buy ammo for my deer rifle? The one my Grandpa gave me?"
Link: https://en.wikipedia.org/wiki/List_of_AR_platform_calibers