I've heard that you should be able to put 50lbs of pressure on your bullet (at least for 45acp) and if it doesn't go down into the cast then you have a good crimp (it won't fall out in a semi-auto).
How (or do you) test crimp by putting pressure on the bullet? I tried by squishing a bullet between two pieces of wood on a bathroom scale but there's probably a better way and I just don't know about it yet.