ORIGINAL: stubblejumper
I find the most reliable pressure sign to be loose primer pockets after a few firings.As such,I usually reuse a small number of cases for a few firings before loading up any large amounts of ammunition.
I read an artlcle by Jack O'conner in an old speer manual that basically stated that was the best test. If your primer pockets are not loose after 6-8 firings of a case, then you are OK. I don't think that would apply to low pressure rounds like the 30-30 and 45-70.