Sometimes commercial spreaders and reloads with spreader inserts will throw "doughnut patterns" with a hole in the center. It's good to check your patterns with same, on paper, before heading out to the courses or the field.
A friend is in the plastics molding business and he's been working to patent and market a new type spreader gizzmo. This is all I can share right now. Just to show what can be done. The patterns I'm posting here were done using a 12 gauge GH Parker Damascus with .036" choke/left barrel
at 20 yards from a sitting rest. I'll keep folks here appraised of progress with the Patent.
Control (just for comparison) - 1-1/8 ounce of Lawrence hard 8's in a Remington RXP wad, in a Remington Gun Club case. Powder was IMR "PB"
at low pressure. Sorry, I'm not a ballistician. Please don't ask for the powder charge; you can easily get that info from the Hodgdon's site.
Same load of 8's also at 20 yards but with his spreader gizzmo
Threaded Mode