My son sent me this. He says it is a double die on a 1972 D half dollar. I told him I don't think so. How do the experts rule.
It's machine doubling, so not a true DD. Its a pretty nice example of MD, so I might keep it anyway though.
It’s definitely doubled but it’s the wrong kind and not a doubled die by any means. It’s a form of NAV, No Added Value Doubling, known as MD or Mechanical Doubling.
Check out some of the free reference guides online, regarding doubling. http://www.doubleddie.com/144801.html http://varietyvista.com/index.htm https://www.ngccoin.com/news/article/5688/Double-Dies-vs-Machine-Doubling/ https://coins.thefuntimesguide.com/machine-doubling-doubled-dies/ https://www.error-ref.com/doubled-dies/
