Their specs are typically 12-16" compound radius. But their Floyd-equipped guitars come with the R3 nut which is 10". Out of curiosity I tried a 12" radius locking nut (1000 series R3) and it did NOT work. The low and high strings were too high, middle strings too low. I also tried the R4 nut which is 10" radius and wider string spacing, and it was perfection. Which makes me think it's actually 10" at the nut and maybe Jackson has a weird way of measuring it? Anyone with a Jackson and a radius gauge wanna confirm? It's for science.