Quick question: are you using plastic wads or card & fibre?

Not a .410 but I have had good luck 20 & 12 bore with card & fibre wads where I infused (soaked) the fibre wads in melted SPG lube. Wonder Lube, Crisco, Olive Oil & beeswax, whatever would likely work as well.
No hard fouling issues……perhaps a bit messy to assemble the loads.
- Mike