It might be interesting to see just how much velocity an equal charge of APP delivers. I do know that, even at the same chronographed velocity, some MZ powders kick more than others. I'm not sure if it is because the bullet starts moving down the barrel more/less violently; or if there is more muzzle blast after the bullet exits the muzzle - driving the gun into your shoulder with a "jet engine effect". But it is not just simple physics - the powder can make a noticeable difference.