not on oricals, but on boss (who has more health than an orical yes) i think golden gun does a fixed amount of damage no matter how tough the enemy, where as most weapons do a fraction of the damage of that enemies health pool, up to their maximum damage value. i could be wrong and cant explain well, but 1 golden gun bullet vs 4 to 6 from the icebreaker depending on range. it also depends on how quickly the orical has been shot at after spawning i tend to find. eg. ever wondered why no matter how high level you are you can never one hit melee a rank 1 or rank 2 vandal, but you could do a dreg at the same level to you.

I've one hit melee's Vandals lots of times.