844 is very close if not the equivalent of H355

if you have some old reloading manuals, (like the Lyman/Ideal) they will have some reduced loads for 30.06 (I'd take a look but I am not at home )

you should be able to find a similar powder (not sure how old H355 is) and work up a load,

as always, go low and work up


I use a 'bumblebee' load sometimes in 30.06 using 168 SMK's and 2400