Quickload Question

[steve4102]

Looking through all the different data available in Quickload I found something I do not understand and could use some clarification.

When QL calculates a load the list several bits of information. One of these bits of info is "Muzzle Pressure".

It appears that the slower the powder the higher the "Muzzle Pressure", even if Chamber Pressures are the same.

What is the reason for increased Muzzle Pressure with slower burning powders?

 

[RiverRider]

All smokeless powders contain roughly the same amount of energy grain for grain, which means that no matter the burn rate, a grain of powder will convert to a certain amount of gas. You can pile in the slower burning powders because of the slower burn and still maintain safe peak pressures but since there's more gas released, the residual pressure will be higher as the bullet exits the muzzle.