Fat_McNasty I'm not even going to ask why they call you that
but I wish I'd thought of that username first.
You stated thin jacket around a lead core. Then scored to allow rapid expansion. Plus a big hollow point of coarse also from looking at pics.
It seems that if someone is mechanically inclined. They could take a SMK bullet or any other thin jacketed bullet of the proper weight. Make a jig of some kind to hold bullet.
First cut enough of the tip off to allow a hollow cavity be drilled using a drill press with the jig to secure bullet. Then just score the bullet after that.
If you set everything up right you could remove the exact same amount of of the tip when cutting and also the same amount of lead when drilled to ensure. To ensure a consistent weight.
Better yet score the bullet before you cut the tip off. You could also counter sink the lead abit after drilling the hollow point cavity.
Then just cut the copper jacket all the way through in line with the scores of coarse just to the lead. Then fold the copper ends over the lead in the hollow point.
I bet depending on the depth of the scores and size of the hollow point. It could work great and maybe take less time once the routine is worked out.
You obviously have expertise in this area. Do you think that this could be done.
Oh yeah bullet could be run through a bullet pointing die to dress it up at the end.