Hj, in case you aren't getting this, the doll's head versions predate the simple slot extension version by some 20-25 years. The Proprietary was one of the later versions of the Screw Grip action, a less expensive version, too. The Screw Grip actions occur in boxlock and sidelock and with a wide range of original quality of barrels, lever work, engraving, wood, and finish. Screw Grip SL's were made in very good grades, but were never "best work" grades. Best work at Scott was the Premiere, which sold at "Purdey money."
