I found a lb of 785 and wanted to try it in a 25-06. I have a winchester ball powder manuel and says loads should be exact as manuel with no substitutions or REDUCTION of load. Does this mean you start at manuels data and work up. I will be substituting components ,rem case, speer bullet, but win primer, and of course powder.how do you think I should proceed?

Mike I believe the 785 loads were to be used as printed. they are close to max so dont try to go up very far. Do not go down as eratic pressures could result.

thanks, I also read somewhere that h450 and it were the same, but I question that.the manuel only gives one load for ea. bullet weight.

The Speer #10 manual has 25-06 data using 785 powder.

87 gr. bullet
59.0 3346 fps
57.0 3210 fps
55.0 3097 fps

100 gr. bullet
57.0 3284 fps
55.0 3121 fps
53.0 2985 fps

120 gr. bullet
55.0 3045 fps
53.0 2918 fps
51.0 2809 fps

I went through this dilemma years ago and ran it on AR.

As I recall the concensus was that I could reduce the loads a grain or two.

The issue now could be that your powder is not new and a line that Winchester deleted for some reason, many years ago.

785/450 was made to be ball replacement for H4831.
They are pretty close, but I have not put into practice.
I have plenty of both, and dont plan on throwing them out.
I will try them one day.

thanks guys

The warning not to reduce loads with WW785 was a precaution against Secondary Explosion Effect, or SEE, a phenomenon sometimes experienced with slow-burning powders. It can occur when there is excessive powder space left in the cartridge case and, as the theory goes, this allows a "secondary" ignition of the powder resulting in an extreme pressure excursion.

SEE has been demonstrated with certain stick powders (the old surplus 4831 is alleged to have blown a number of then-wildcat .25-06's due to too-small powder charges.) So far as I am aware, it has never been demonstrated in ball powders, but with WW785 having a similar burning rate to surplus 4831 the company erred on the side of caution and posted the warning not to reduce loads. However, a load reduction from "full pressure" would have to be in excess of 10% for SEE, if it actually could occur with a ball powder, to rear its ugly head.