Steve Davis has made no further comments on number of PDR locations. He spoke from the perspective of the boat-tailed, long-ogived, pointy bullets. On a flat-based-flat-nosed bullet we are absolutely correct. The more the merrier, as long as the wavelength of the PDR band is the same, repeating every 0.100" of run in the shank of the bullet, and not just increased in frequency to increase the number of the "bands and grooves."
What little I know about the patented PDR bands is that they work very well on a bullet. "Parabolic Drag Reduction" is what the acronym stands for, not "Physician's Desk Reference." Easy to remember acronym.
I SWAG they are a sinusoidal pattern with peaks and troughs like a wave form. Peaks are 0.0005"greater than groove diameter: 0.4585" for a .458-caliber. Steve Davis stated that recently, as you read. I SWAG the troughs are about 0.001" to 0.002" less than bore diameter, so 0.448" to 0.449" for a .450-bore. No confirmation of that by Hammer. Might be 0.0005" to 0.0015" sub bore. Not sure. Whatever it is they are working at 0.0001" capability, and I am working at 0.001" capability.
They buy the special alloy copper that they use in 10 or 12 feet lengths of rod. Surely they have to spin some length of the rod in the CNC machinery, advancing it as each bullet drops off the cutter end.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
