9mm Rounds won't seat

[cfmitch]

I don't have any problems with my 40 S&W nor my 45 ACP, but these 9mm are driving me nuts. All the cases are trimmed to right length. I am using RCBS dies. I use a case gauge to check the cases for chambering. The problem is that the case heads will not sit flush after loading a bullet and putting a slight crimp on it. All the cases have been "belled" to start the bullet. Any ideas out there? I loaded 10 rounds and 6 will not seat flush into the case gauge.