Wow mustang you are confused.
Volume measures are the quick and easy way to load charges for the average plinker, hunter whatever. Extreme example is a cup of plastic BBs and a cup of Lead BBs, same diameter projectiles, same volume, yet drastically different weights.
Grains are a unit of measurement, 7000 of them make up 1 pound. If you look at a grain of powder it does not equal a grain in the powder measuring terminology.
Volume measures are the quick and easy way to load charges for the average plinker, hunter whatever. Extreme example is a cup of plastic BBs and a cup of Lead BBs, same diameter projectiles, same volume, yet drastically different weights.
Grains are a unit of measurement, 7000 of them make up 1 pound. If you look at a grain of powder it does not equal a grain in the powder measuring terminology.