The jackets are gilding metal, not cupronickel.
The Nosler jackets are extruded, so I do not believe it's a blank made into a 140 jacket and then trimmed to the 120 length. Rather I believe it's the same blank to start, but it doesn't get extruded to the same length. Hence it remains thicker to the tip end of the side walls.
Whatever it is, it is a deer killing machine.
