Blackhawk comes to an end with issue 273 (Nov 84). Evanier's story includes a Detached Service Diary as a flashback, integrated into the tale.
The Blackhawks head to China in the Spiegle story, and we finally get to see the new weapon the Japanese have, a giant robotic dragon.
Not only does the story bring back Chop Chop, is also brings back Virgina Mueller, the American reporter who had been featured in a Detached Service Diary tale, in which she, at first, thought the Nazis were no threat. In this story, she hears about the Blackhawks being sent to China to deal with the weapon, and coaxes her editor into sending her there. She actually arrives before the team do. That point will come out later in the story, as the Blackhawks wonder who alerted Virgina, before they themselves knew where they were going. But since the series ends here, this mystery never gets explained.
Sekowsky and Howell do the art on Detached Service Diary part of the story, which relates how he arrived as a Blackhawk in China.
Chop Chop has been fighting to defend his people, and was the first one on the trail of the new super weapon.
Chop Chop gets captured by the Japanese, but escape and joins up with the rest of the Blackhawks as they lure the "dragon" into a building full of explosives, detonate them, and destroy it.
The story ends with Chop Chop returning to the team. The Blackhawks tell Mueller that she cannot write anything about this battle, until they learn how she was manipulated into coming to China.
The Blackhawks are next seen in Crisis on Infinite Earths. Chaykin would be the next to revive the team, in a miniseries in the ate 80s.