What about trying a 'shot wrap' of some sort of plastic in front of the over-powder wad? Might be illuminating to compare patterns. Or, come to think of it, a 38-cal shot cup might work OK too.

This might be just the ticket for unwanted birds in the hangar, and lots more fun than any rotating light! Or rats in the basement, or marauding dogs in the garbage or......
Regards, Joe

You can lead a man to logic but you can't make him think. NRA Life since 1976. God bless America!