I tend to think anything cutting onto another surface is not designed for large amounts of cutting. With wad punches I find a fair bit of force is needed to slice into the sacrificial surface to get a clean cut in the material I'm cutting.
Anyway, I've now found a video of a proper 12g punch which is useful to see the cutting punch and the holder. I would be tempted to just buy one if they were available in the UK but at least it gives me a few ideas of what I could make.
Here's a video if anyone is interested. https://www.thereloadersnetwork.com...ell-filler-wad-overshot-card-punch-completed/
Anyway, I've now found a video of a proper 12g punch which is useful to see the cutting punch and the holder. I would be tempted to just buy one if they were available in the UK but at least it gives me a few ideas of what I could make.
Here's a video if anyone is interested. https://www.thereloadersnetwork.com...ell-filler-wad-overshot-card-punch-completed/