The problem isn't hand cannons. They've stated before that accuracy will fall off when fired at long ranges. Hawkmoon now no longer has a long range therfore will not consistently hit its target when where you're shooting it from.
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Hawkmoon can still be made to have a a very good range stat for a hand cannon, and yet it still misses shots like this. A typical legendary hand cannon with even lower range suffers just as bad, if not worse.