Help: 7.62x54R 1920s solid tombac experimental bullets?

This is a new one to me guys, a friend comes up with these:

received_1928794617221524

He says they are an experimental 7.62x54R solid bullet, “tompak” he said. Something might be getting crossed in translation there, I’m guessing some sort of solid brass type for increased penetration. He is a page of information he sent:

Anyone here got some more info on these? Thank you.

Not really experimental but more of an interim measure.

Tombak is the same as gilding in English: brass with 90 percent or more copper.

An interim measure for?

They had AP rounds by this point in history.

Civil war and a newly set up factory are legit reasons to call it “interim” I think.