Thanks guys

Yesterday as it happens I picked up about 400 used carts from a very helpful guy at Gatwick Clay School. Mostly Eley 1st 67mm but a good 100 or so 70mm Lyalvale English Sporter 70mm which I think are the ones I'll use.

I know the Eley 1st are a cheap cartridge. Does that mean they are less suitable for reloading?

As for load, I found a place called Folkestone Engineering Supplies who supply all the stuff I need and also give suggested loads. I'll be looking at the fibre wad, 34g No6. They suggest:

70mm Case
1.7g Maxan CSB3
4mm card
16mm Fibre Wad
34g #6 shot
Star Crimp

I guess if I go for the shorter 67mm carts I'll have to reduce the shot and powder?