The result of your conversion between petajoule and grain/ounce [US] appears here
To convert between Petajoule and Grain/ounce [US] you have to do the following:
First divide 1.0e+15 / ((0.45359237/16)*(192/175)/480)/(0.0037854118/128) = 456389307898851.9375
Then multiply the amount of Petajoule you want to convert to Grain/ounce [US], use the chart below to guide you.
Symbol: PJ
No description
Symbol: gr/oz
No description