I shoot this cartridge on a regular basis, Hogden no longer makes H870 powder, which was one of the main powders used in this loading, so you'll have to find a substitute powder. WC872 and Accurate AA8700 (8700 is slightly faster than H870) are two good choices for powder. I use AA8700 and here is the loads that I use :
Target load: 78 grains AA8700 with 140 grain Sierra Matchking bullets and Federal #215 primers.
Hunting load: 76 grains AA8700 with 140 grain soft point bullets and Federal #215 primers.
I believe that Accurate has discontinued the 8700 powder, but you can still find WC870 which is a militart surplus powder, and you can use the same load data as H870 with WC872. AA8700 and WC872 are both spherical (ball) powders and do not erode the barrel like extruded (stick) powders.
This is the load data that I have for H870 and a 30" barrel:
82 grains, 140 gr bullet, 30" barrel, velocity 3,239, Winchester case
83 grains, 140 gr bullet, 30" barrel, velocity 3,309, Winchester case
86 grains, 140 gr bullet, 30" barrel, velocity 3,527, Winchester case
I hope this helps you understand!