Unknown in a 30-30 case

Does anyone know what this might be? It’s a 30-30 case with a modified rim, and a semi-jacketed hollow point:

Looks like a 401 Winchester self loading made from 30/30 brass. What is the bullet diam and case length?

The 401 was loaded with .406" bullets and has a 2" case.

I don’t have the cartridge with me, it is from an internet photo, but I will see if the owner can get me the diameter and case length. Thanks