Powders go kablooey when loaded wrong. If your going to insist upon using a POWDER you don't have data for then please hide behind a huge tree and fire your gun with a rope. Pressure curves can violently destroy a gun and you with it. Now, with bullets it's a different story to an extent. Similar bullets have very similar friction and react to pressure similarly, so if they aren't identical they will be very similar. Varying weight or construction changes that reaction to pressure, but again these can for the most part be understood and figured out with a well thought out ladder test.
Reloading is an art, but it is more than that since your work can easily mean the difference between going home like you came, or going home missing fingers, teeth, eyes, or nostrils. A man can take dead reckoning to a certain extent based on knowledge, but even doing that means that the man accepts a certain degree of risk. With no knowledge of a certain powder you can't even do that with an acceptable level of risk. You have to assume it will cost you body parts. Even the pros use test methods engineered for safety to build their knowledge base before taking any risk be it acceptable levels or not. This is not a guessing game nor is it simple arithmetic. Please leave the big questions to the pros and use their data to build your knowledge base. The little questions are the ones that you answer by building a load for your own gun.
