[Marcello]

"Which is better?"
APDS and APCNR are both better than APCR. Between APDS and APCNR it is a bit harder to say. APCNR is a one trick pony, in the sense that you can only fire efficiently AT rounds (the HE shell sucked, especially for the small calibers, given that it had to fit a taper bore barrel) and you have to deal with higher barrel wear. Further you need a secure supplies of tungsten for the rounds (and managanese for the barrel); while with a conventional gun you can supplement your APDS with conventional AP this isn't as easy with a taper bore design.An APCNR might,but I am not sure, be lighter in construction; this would be handy for a towed antitank gun, like the PAK 41 was. But for large caliber tank guns I think you are much better off with a conventional barrel and APDS rounds. Frankly I am not even sure a 150mm taper bore design would be feasible in first place.