Jakura Nuva

Exactly. Hardshell the Insecticon was introduced in the Aligned continuity.

I don't remember the Headmasters at all, and I'm always getting Bombshell confused with Hardshell, so... (And in my world, the Headmasters aren't cannon, considering they're just humans in robotic heads)

The only reason Hardshell exists is because Hasbro failed to get 'Bombshell' trademarked. Hardhead has nothing to do with him.