I used a Bianchi #5 (0613) for my square guard 45-06. I custom fit the 4506 by soaking the holster in a 50-50 solution of alcohol (rubbing!) and water until the leather was saturated. Crammed the gun (wrapped in kitchen plastic wrap) into the softened holster, working the leather around the various curves and trigger guard. Attached the strap and left overnight until dry. Finished up with a good coating of leather conditioner.