National Institute of Justice is taking in public comments for new NIJ standard. Instead of Level II, IIa, III and so forth, it will use more descriptive terms such as Handgun I, II and Rifle I, II, and III
https://www.nij.gov/topics/technology/standards-testing/Pages/comment.aspx
You can look at page 7 and 8 for what type of ammunition will be in each class.
