[Mozzy]

Is it a Leopard motor by chance?

You're right about your set up, it sounds just fine.

If I were you, I would try a different motor.
I heard from a guy that bought a Leopard motor (not saying yours is) & it heated up the wires & was running well within it's limit, but, it ended up frying his ESC for some reason. He has never discovered why nor has had the opportunity to run a different motor for testing on his now toasted ESC's.

Just some ideas I thought I should throw out there.