Definitely cupronickel jackets. The tiny bit of lead exposed on the tips is strange though. Cupronickel was universally used up until the WWI era and shortly after. Big PIA because of the fouling it generated in the bore with extended use. Gilding metal like we have today fixed that.

"You can lead a man to logic, but you cannot make him think." Joe Harz
"Always certain, often right." Keith McCafferty