The result of your conversion between grain/cubic foot and grain/gallon [US] appears here
To convert between Grain/cubic Foot and Grain/gallon [US] you have to do the following:
First divide ((0.45359237/16)*(192/175)/480)/((0.0037854118/231)*1728) / ((0.45359237/16)*(192/175)/480)/0.0037854118 = 0.13368056
Then multiply the amount of Grain/cubic Foot you want to convert to Grain/gallon [US], use the chart below to guide you.
Symbol: gr/ft³
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Symbol: gr/gal
No description