Quickload and predicting cycling?

[Whispering_Thunder]

I've got a bunch of powders and I'm trying to do some experimenting as to what will cycle my gun. Chamber pressure does not seem to be a good indicator (I'm running about 19K psi on a 150gr and it cycles, while 36K under a 225 pill won't). Is there a formula that would be good at approximating it or a number indicator in quick load that would help?