[Wonder Warthog]

"Probably much quicker to put the bar in a CNC machine and hollow it out, than it is to go through the molding and casting process. Then polishing up the cast bar carefully so as not to remove details or leave marks."

VERY unlikely. I've done a LOT of machining. Gold is !SOFT!. I haven't worked directly with gold, but other metals with similar physical characteristics that I have worked with (tantalum, lead) are VERY difficult to machine, even with CNC.

And I doubt that the sort of folks likely to be doing this have access to $100K CNC devices.

Making a casting mold, OTOH, is very "low-tech", cheap, and easy. The "hobby supplies" market probably has all anyone needs to do the necessary.

[ltc8k6]

I’m sticking with what I can see. The tungsten bar does not fit exactly into the opening, so it can’t be a casting process.

I think we can see a logical progression.

They started off by drilling out the bars and inserting tungsten rods.

Then they figured out that they could hollow out the whole bar and insert a tungsten block.