There is no real substitute charge.
What you can do is email the actual powder manufactures.
Not the name on the bottle.
Look on your bottle and see where it was made.
Call the powder brand name and ask who actually manufactures XYZ powders.
For example there is a lot of powder made in Australia for many different powder vendors.
ADI... this chart does not say they are the same powders. Although should get you an idea.
http://www.adi-powders.com.au/handloaders/equivalents.asp
There are a few powders which are the same yet labeled different. Only the manufacture can tell you that.
What I have seen is you need to look at the slight changes.
Varget and 4064 might be darn close in that low to mid range loadings but one may spike in pressure quicker as the charges go up.
If you see that a powder you have is not turning up in load data books 2 things going on.
Either there is not a decent load worth printing with that powder or their is money involved in what and which powder is listed in a manual.
In the end either buy the powder you have data for or call the manufacture both bullet or powder.
