I see my post back on the first page of this thread is from before I got Rudy Kostelecky's copy of the Three-Barrel and Royal Gun Co. ledger for the three-barrel guns. Rudy's Gun Shop in Cantonment, Florida, had a lot of the remains of the Hollenbeck/Three-Barrel/Royal Gun Co.'s back in the day. From the ledger we can add .25-35 WCF and .25-36 Marlin to the rifle calibers.

Give me the serial number on your new toy and I can check what the ledger has.