anything before now is considered as in the past for some people,
1876 , well for me thats modern or at least semi modern stuff
yes there is a reason to why all original pieces was cast standing , and thats the quality of the casting
if its cast standing muzzle up without a core you probably got most of the impurities, slag and porosities in the shrinking head (feeder)
with todays chemicals as flux , degasing and desoxidation you can have an almost perfect casting .
if you add an ceramic foam filter and have an perfectly controlled temperature for your alloy you cant get it much better without having some very complex equipment
next step would be to flush the mold with argon gas just before and during the pour
but the question is where to draw the line between good quality and insanity
or vaccum casting
centrifugal casting
the posibilities is endless if you want to spend a million dollars or so
but are we talking cannons or some very critical parts for nasa ??
silicone bronze is an extremely nice alloy to cast , but Im not sure how suitable it is as an gun alloy
Im sure someone here could check it up for us