Looking for a new or fairly new Mec 9000 H with or without the pump and motor as I have a 9000H already but having problems with the deprimer station after knocking the primer it also bulges out the head of the base of the hull.
For some reason, it sounds as though your shell is not dropping all the way down in the sizer collet. Cleanliness and lubrication is key. Take it apart and clean in solvent then put it back together and lube the OUTSIDE with preferably "MEC collet lube" or good anti-sieze available at most auto parts stores.
The other guys said it. You don't need a new machine.
Make sure the rod is sliding and dropping down smoothly on station #1. Any lube on it will gum it up and keep the rod from sliding smoothly and then the hull won't drop all the way down.
Your hull not dropping to the bottom in #1 is the real issue . Now what is causing it?
A pellet stuck in the petals of the collet will also do it. I use a dental pick to check in between the petals when needed. So will a slightly misaligned turning plate. Make sure it rests snug against the plate stop that I think is just the other side of station 3. The collet should be lubed or that will also do it. I do that by holding the foot pedal down and lubing the outside of the collet. I also have an H and I think that because the hydraulic pressure is strong right from the initial pressure on the foot pedal, everything has to be just right. By the time the foot pedal squeals from the pressure of mushrooming the hull it's too late.