AB, you are much more likely to damage the action with a diet of modern high pressure loads than burst a barrel. Getting new 2 3/4" chambered barrels doesn't solve your issue at all.
BP loads are not necessarily safer to shoot nor are they necessarily easier on the gun. BP and "normal" nitro loads have very similar pressure-displacement curves. BP burns much hotter than modern nitro powders and is far harder to clean. There are plenty of 2 1/2" and 2 3/4" low pressure light shot loads from the factories and reloads.
