My first reaction was also CH Auto Champ. But I'm not sure. There's no markings anywhere?
I had a similar press, an RCBS Green Machine. It was fast, but kind of a nightmare. I tried a caliber conversion once and had to call RCBS. After talking to one of the RCBS engineers I got the issues cleared up and after some use successfully converted it back. The engineer told me they quit selling conversion kits because everybody had problems pulling it off. That one machine was responsible for most of their support calls. But they are fast.
One problem was if a case failed to feed it would dump powder in the rails and it was disassembly time. Plus the primer magazine was right on the front, directly below your face. No shield.
I bought a Dillon RL450 and sold it.