Same as David Tubb uses 70 nm MK-hBN-N70-Nano. 1 micron is 100 nano-microns. So, 70nm is about 1/2 the size of 1 micron, 1/4th the size of 0.5 microns.
Three grains per batch of 50 to 100 bullets works many people report. Place in sealed container with lead shot or BB's then tumble or vibrate...