http://www.blackhorn209.com/files/pdf/Black%20Horn%20Cartridge%20III.pdf
There is some pressure data but it relates to 45:70 & 45:120 ect.
It was published when they came out with BH209 that the peak pressure runs about 5% lower than 777; my strain gage testing agrees with that, even so the longer pressure peak causes more blow back because the pressure is up longer. The burning rate is so much different than TB that the ratio would be meaningless. Lee