Copied this from DGCR:
This was pretty buried in the PDGA web site under competition manual in technical standards:
A disc shall:
(3) not be less than 21 cm in outside disc diameter, nor exceed 30 cm in outside disc diameter;
(4) not exceed 8.3 g per cm of outside disc diameter;
(5) not exceed a maximum weight of 200 g;
A 21.1 centimeter diameter disc (most drivers) times 8.3 grams = 175.13 grams max allowable.
Meaning Midranges may be heavier than drivers as they have a larger diameter. While using Max weight Drivers means 175 g, Max weight for Mids depends on their Diameter.
Plus, I think I read that somewhere on here, there is some kind of production tolerance which is +/- 3g. During the injection molding process when the disc is made, you have process variations due to several aspects so the weight of the part you get can be +/-2% of what your data in the machine says. That's why you have +/- 3g in tolerance for a disc, so you might even get a 177 Destroyer labelled as 175 which is legal then (I think). Depends on if it's being weighted and then labelled oder labelled by the data you put into the machine....I hope you know what I mean