I have on hand a supply of 870 and want to use it in my 300 Wheatherby. I also want to use 165 grain bullets. I have been unable to find any data. I think 95 to 90 grains is a place to start, does anyone have any thoughts ? thanks.

H-870 From 88.0 grains to 94.0 grains
Federal 215 Primer

FWIW--I had a pound of it a few years back thinking it would be wonderful in the 300 wby and my 7mm mag. It was awful--awful dirty and awful slow. (like many velocities were about 250 fps below hogdons books). Maybe I got a bad batch but I bought it fresh at my gunshop--not something from a gunshow that might have been sitting around a long time. Hope you have better luck. I've seen people get along with h870 but it sure didn't work so good for me. A chrono would sure be useful for load develpement for you.

Witness, the proper load of that's going to be as much as you can fit in the case. Seriously, that'll be a mild pressure load. It'll make a lot of muzzle flash and blast. Crimp it tightly if you want to get good ignition and reasonably clean combustion. Use magnum primers.