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This drill is .076" and the original port size is .077". More than likely with a cheap drill press or hand drill the bit will cut oversize so it won't really matter. The original hole looks to be drilled with a .156 or 4mm spot drill then drilled with the smaller drill bit.
All the drills that I buy are the screw machine style which is shorter and will flex less than normal jobber drills that you buy from the hardware store.
The picture doesn't show the drill, but only the drill will be sent not the gas block obviously. The picture shows how the hole should look after drilling.