What does sp circled on a sears roebuck and co shotgun mean?

The "SP" circled on a Sears, Roebuck and Co. shotgun typically indicates that the firearm is a "Standard Proof" model. This designation often signifies that the shotgun has undergone standard proof testing to ensure it meets safety and performance standards. Sears sold firearms made by various manufacturers, and such markings can help identify the model's specifications and quality assurance.