I shot my first rounds of WIN LB 3"#6 in 71 * temps today and the worry over resin dust is over. The powder showed up about 20 feet it seemed from my muzzle. The patterns were very acceptable at 38 yards in my Win Supreme O/U using 660 and 675 chokes. I will be trying it in a BPS later. This will be my new lead shell preference in 12 gauge with my Win Supreme XX other loads still not bad at all.
And no, there is no chance that the resin particles are part of the target pattern at 40 yards for sure.