I was looking for the website where the guy has the military powder that is just like H-870.I have a 264 win mag that loves H-870 but I cant find any more.
On the powder burn rate chart, H870 is right inbetween RETUMBO and H50BMG. Both are readily available. Most dealers keep RETUMBO in stock, which is the more popular of the two.
H870 has not been discontinued that long. I would imagine that there is some still floating around that could be located.
For a substutute for H870 you might try WC872, it's supposed to be a slight bit slower but was told to use 870 data to work up loads. Pat's Reloading has it for $36 for 8#'s. And Bartlett Reloaders also sells it.
Wayne
According to my chronograph the wc872 will not produce the velocity grain for grain with h-870. But it is still a very consistant powder in my 300 win mag.