In the U.S., both bullet weight and powder charge are stated in grains. Most ammunition boxes will not list the powder charge (it varies with different powders) but do list the bullet weight. In general, the lighter the bullet, the higher its velocity at the muzzle.
On ammunition boxes printed for those who "speak metric" (which is most of the rest of the world), bullet weight and powder weight will be given in grams. Most ammo sold here, regardless of origin, will have boxes marked with the grain weight of the bullet or, sometimes, both grain and gram weights.
The abbreviation "Gr" is usually used for "grain". The abbreviation "G" or "g" is used for "gram".
Jim