These mounts were made by Recknagel for Blaser. You can still buy most of the parts today from Recknagel. The exception is the front ring and the barrel-mounted socket. They are custom items specifically for this model. But within this model they interchange. I have 5-6 sets of front rings with barrel -mounted sockets and about 15 rear rings if you need spares. They came from the old Blaser importer Harold Hayes.