lead alloy is the same
the temperature is the same
the mold is the same and at the same operating temperature
the only thing that is different is the hole in the ladle and the bottom pour pot
Lyman dipper hole size is .185 dia.
Magma hole size is .086 dia. from their web site instructions on cleaning
Lyman mag 20 mine is .115 dia. but i have drilled this one oversize
my speculation at this time is that the bottom pour pot manufacturers do not want a large hole because it may splash with the faster moving more volume flowing alloy from a larger size hole so they use a smaller hole.
and i think that the hole size is why the ladle with the larger hole size work better because they fill the mold faster with more pressure on the metal which would force the alloy against the sides of the mold, it would also mean that less air would be introduced into the mold when the alloy is being poured because of the larger faster fill
i plan to enlarge the hole on my mag 20 to the .185 dia size but i will have to make up a new valve rod as mine will not go any lower unless i move the op handle slot upwards
any comments are welcome and please add the hole sizes of your equipment