A Jack jumped between a Solar and a factory in this game. I think the interaction was approximately fine. I am certainly not going to tell people they can't do this.

Ideally when a Jack jumped between two structures like this, it would be shootable from a reasonable range of angles. Failing that, the answer is to Self-D the Solar. Failing even that, perhaps building Solars next to factories is a trap, although at this point I'd bump up the priority on reaching the ideal.

Also, the game doesn't say much about how close we are to the ideal, since the Solar was killed by Magpie AoE, so there was clearly some way to fire at it.

Hitbox is the same. And the hitbox barely covers the closed size anyway.