The treatise here says the difference between a 2.5 inch shell and a 2.75 shell from a 2.5 chambered gun amounts to an increase of 300 -400 (on average) increase in psi, insignificant.
The catch is that as chamber pressure goes up, the longer shell will go up quicker. The longer hull will reach ugly pressure sooner than the shorter one.
Does that translate at all to 2.75 and 3" shells?
The concept does, but the #2 kicker is that there aren't very many low pressure 3" loads. Unless you truly know what you are doing, 3" loads in 2 3/4" chambers are ill advised.
The variables in the equation are a given. Each length shell is loaded to the same configuration.
Take a 2.75 magnum shell at 1500psi with 1 1/8 shot from a 2.75 chamber. That is a standard 3" shell. Is there an increase of pressure if you were to shoot the 3' from the 2.75 chamber?
I don't know, but I'd advise against it.
DDA
