I don't remember where I gathered this information - it's been a while, but the differential is not that high - 0.032. The RG was supposed to be in the low 2.5 range, say around 2.51 or 2.52. I have both a Bruiser and a Fire Quantum drilled almost identically, and the Bruiser flare rings are farther apart than the Fire Quantum's, which verifies the differential figure. The balls reaction leads me to believe that the RG figure isn't much different than the Bruiser's either.