The result of your conversion between Btu and grain/ounce [US] appears here
To convert between Btu and Grain/ounce [US] you have to do the following:
First divide 1055.0559 / ((0.45359237/16)*(192/175)/480)/(0.0037854118/128) = 481.516232
Then multiply the amount of Btu you want to convert to Grain/ounce [US], use the chart below to guide you.
Symbol: Btu
No description
Symbol: gr/oz
No description