A knowledgeable cartridge collector in Germany gives it as the 10X60R Roth and to fill the case to the base of the bullet w/ black powder & let if fly. Pretty corrosive I must say.
Sure, using BP and "filling up the case" is an easier approach than NfB.
Still there are some complications: "Any black powder" will NOT do.
E.g. you can generate a lot of bang and peak pressure with too fine BP.
Using over-powder wads or not is the next question.
Bullet choice will be critical to get sufficient accuracy
(BTW, why zinc bullets? One more complication.)
Corrosion can be handled by good cleaning procedures, for rifle AND cases..It is messy, agreed!