The second video I found had the guy spill half his bucket (not sure of the correct term) of molten bronze on wet concreate. I can be a bit of a dumb@ss, but even I know to avoid that. I will not link because I do not want to embarrass the guy.
This one looks more like they know what they are doing, and they are trying to use 15th century techniques:
For anyone further interested, I forgot that I found their report on the cannon casting project. Some interesting additional information.
One particular fascinating detail is that the research group went to India to learn more about low tech bronze casting, because they still use traditional techniques for casting large religious objects and there is a preserved cannon foundry.
The report is the PDF attached.