bullet and propellant weight is measured in grains... there are 7000 grains in a pound
the amount of energy in a propellant is controlled by several methods
most smokeless propellants are nitrogen compounds containing ... nitrocellulose.... nitroglycerine... nitroguanidine and referred to as single, double, and triple based propellants, depending on the relative mix of the three
burn rate is controlled by shape,.... flake,.... spherical,... extruded (sticks) as well as any burn rate reducing coatings like graphite
typically target loads on a commercial level are light charges of "fast" burning powders to make the cartridge economical to produce... while "magnum" loads are large volumes of "slow" burning powders, typically needing a primer of high initial energy
a particular volume of propellant will produce a certain volume of gas with which to propel the bullet...more volume (weight) of powder equals faster bullet... but since the breech end of the open barrel is only sealed off by the expansion of the cartridge case there are pressure limits...blow back actions and locked breech actions have different safe levels... bullet weight and charge weight by propellant manufacturers are listed in reloading manuals and are keyed to the max recommended pressure
I use Winchester Super Field which is a medium burn rate shotgun propellant for 9mm.... a 3.6 grain load behind a 135 grain polymer coated cast bullet gives me about 1080 fps out of a 16" AR 9mm carbine... the same load out of a Glock 34 is about 950fps...
regards Les