Convert from mercantile pound to gigagram

Unit Definition (mercantile pound)
The mercantile pound is a historic English unit of weight, the mercantile pound (libra mercatoria) was the commercial predecessor of the avoirdupois pound. Used from about 1100 to 1300, the mercantile pound contained 15 troy ounces or 7200 grains. This is equivalent to about 1.0286 avoirdupois pounds or 466.55 grams.

Unit Definition (gigagram)
An SI unit of mass equal to 10E9 grams, one million kilograms, or 1 kilotonne (1000 metric tons). This unit is used in scientific contexts, such as the measurement of atmospheric emissions. One gigagram equals about 2.2046 million pounds or 1102.3 U.S. (short) tons.