Sorry Peter, the Izod test is an impact test that breaks the material the Brineell test is the other hardness test but it uses a 3000lb load on a 3/8" ball so not really good for bayonet parts LOL. they do use a lower weight and smaller ball but this is not used as much, Europe went to the Vickers tests for smaller items. I quoted to test the SA80 breach block and it had more indents that my AK47 had parts :-(