Ron........With 209 primers being all different lengths. How can CVA accurately set the head space? All they can do is be on the safe side of the longest primer. The idea of crushing the primer to remove blowback is not something a factory will do.
So, all a CVA can do is pick one primer to use all the time and shim the headspace to that primer. They can also take the easy way and use an o-ring. I personally, don't like using the o-rings. They shim out the primer too much and the primer falls out too easy. Installing the shims is easy enough.