I have Chicago pneumatic composite 1/2” impact guns, and the battery impact gun kills them, and rated at 490nm or thereabouts from memory. I’d say roughly equivalent to my 3/4” ingersoll rand gun but at 1/4 of the weight lol. However, that gun is probably 30 years old and wouldn’t compare to more modern pneumatic tools.
Trevor, no I haven’t measured it. As immortality said, I generally rattle them up with the impact gun and then use a torque wrench as required. Can be very handy where working with larger bolts where torque settings aren’t so critical.