Black powder centre fire shotgun load

[Rockhopper]

I have an old black powder shotgun that I want to reload for.

I have some 65mm primed cases.

I have a tub of Pyrodex RS (no BP licence just yet - maybe in the future though).

I have 10kg of No 8 lead shot.

I have some fibre wads that I'm going to lube.

I have a Lee Loadall to do the crimp.

What I'm struggling with is finding suitable load data. I'm familiar with reloading for my rifles but when they start talking about "100 grains by volume" rather than by weight then I get confused. How do i weigh by volume?

Can someone explain in simple terms what I need to do!!

[Sim G]

You need a black powder measure. That will graduate in grains of black powder. 100 grains of black powder on the measure, is what that weight will take up volume wise. Use that volume setting to then measure out Pyrodex, you will have your charge weight by volume but on a scale may register only 91gns of Pyrodex when actually weighed. But as mentioned, it is the volume of BP that is the standard...

As for your loads, you want around 80gns of RS by volume. An overpowder wad then a "piston wad" of cork or felt. Pour in your shot, about 1 1/4 to 1 1/2 oz, then crimp so that there is a tiny hole left in the centre of the crimp. You're going to have to experiment with the width of wad and/or weight of shot. The goal is to have the powder very slightly compressed by the wad/shot tower, do that the crimp is well formed.

[Rockhopper]

Perfect info - many thanks :-)