About 6 grains of RD under 3/8oz of shot would be a similar (very slightly heavier actually) loading to the old standard 3DE-1 1/8oz in 12ga based on load density. This load in the .410" bore would undoubtedly run a bit higher pressure than the 12ga load.
It is true the .410 can take higher pressures without destroying the gun as most are built on larger frames with thicker barrel walls. However I personally would see such a load as only being useful with small size lead shot. High chamber pressures are not a good thing on little lead spheres & when it comes to patterning the .410 NEEDS all the help it can get.
"IF" of course one had a very nice little 32 gauge then 6-8 grains of RD with a ˝oz load of shot should be a very workable light load giving much shooting for the Dollar.
