black powder burn rate?

[sniper's mojo]

Tried this thread in the reload forum and got no response, so I thought I would take a stab here.

I am newer to this site and have done a search in the old threads for this issue but could not come up with an answer. Hopefully I am not repeating an old question. I was curious how much pyrodex a 26 inch barrel can burn as compared to a 24 inch barrel? Both of these guns have a 28 twist and are rated at 150 grains but I have been told that this is not a realistic estimate of what these barrels are capable of burning. I have had good luck in the past with 100 grains and a 240 grain bullet in the 26 incher and dont intend to change, but I am curious if there is a definite answer or equation to figure out how much powder is being wasted if you load 150 grains in her?

[fulldraw]

When you proof a barrel I believe they use either 3 or 4 times the maximum charge, but I don't think you want to put that against your shoulder.

fulldraw

[john warren]

there is only so much to gain from increasing loads. much above a standard load and your not going to gain enough performance to make it worth burning the powder. i think it has to do with the increasing volume of the barrel as the bullet moves forward. but i may just be making this up.When you proof a barrel I believe they use either 3 or 4 times the maximum charge, but I don't think you want to put that against your shoulder.

fulldraw