Jachin,
Sounds like you've got your crimp right now if your shooting those kind of groups at 10 yds. I reload 9mm also and have loaded thousands of them. I've had problems with to much crimp in the past also. For me it depended somewhat on what type of bullet I was using wether it was a copper jacketed bullet or a copper plated bullet. I've found the copper plated bullets can be overcrimped much easier. This might not be the most scientific way to test, but I first measure the oal, then put one in a clip, load into the gun and rack the slide. I don't put any powder in the test round. I'll do this to the same bullet a few times and then measure the oal again to make sure it hasn't changed. I use just enough crimp so the round can be loaded into the chamber with no change in oal.