The castings of back then were made by centrifigul casting. The equipment was different though.
If you can picture back when we were young, we attached a string to a small weight and spun it around. The same principle was employed in casting also. They used the investment pot as a casting frame. A chain was attached to the rim, molten metal was poured on the sprue and the investment was spun around.
Another approach was steam casting.
Much find gold work was done with steam, using a potato!
Beeswax was used as the model, and a ceramic slurry was poured around the wax. The wax was burned out, also fixing the ceramic.
Now, a larger than what we would call usual sprue hole was opened up prior to burnout. The wax was burned out, and then metal was molten on the mold. A potato was cut in half and put on the molten metal.
Imediate fillout. The steam pressure forced the metal into small voids. I have done some good castings this way. I have done this with a paper towel in a can also.
So they could make intricate castings back then. They just had to make their own equipment and it was a little more difficult to make. This is on top of sand casting.
Sand casting I have difficulty with, investment I am comfortable with.