[Delmar]

I am trying to understand the supposed great difference in pressure between similar weighted bullets in black powder and smokeless loads. For example, if you loaded a 200 grn bullet in a 45 acp cartridge with a smokeless load that achieves 900 ft/second, how is the resulting pressure not virtually identical to loading a 200 grn conical in an 1858 Remington with enough BP to achieve 900 ft/second?