Children of the Grave Jhin

Hello dear RIOT, and whoever is reading this

Just played an ARAM match, where our Jhin was ultied by Mordekaiser. After he died, the clone was attacking us, and the damage was somewhat on the high side. He did not use any ammunition, and dealt around 800 damage per hit.

Is this how the interaction is supposed to work, or should he actually use ammunition?

Thanks in advance.