This heavy barrel half stock rifle is marked "SLOTTER & CO. PHILA" on the top flat behind the rear sight, and the left rear flat is marked "GAIN TWIST/WART/534". The barrel tang is marked "21". The front sight is a brass dovetailed blade, with a fixed dovetailed rear sight. The lock plate is marked "SLOTTER & CO. PHILA". Brass mountings with patch box and crescent buttplate. Double set triggers and wooden ram rod. Straight grip half stock with checkering on the wrist, cheek piece, and fancy trigger guard. Slotter & Co. are probably better known for their pocket pistol fashioned identically after the Deringer, with the company being formed by former Henry Deringer employees. One could argue a case for the aforementioned gun being a Plains Rifle due to the large caliber and rugged design.