The P was a Remington Arms Co. stock letter used in the later years of the the Remington Hammerless Double Barrel Shotgun production. The Model 1894s had a P and the Model 1900s a Q preceeding their serial numbers. Your gun is what is called an EEO-Grade. Actually, E is the grade, the second E is for Ejectors and the O is for Ordnance Steel barrels.
The only higher grade was the "Remington Special" --
From the 1908 Remington Arms Co. catalogue.
Remington Arms Co. ceased their production of break-action shotguns in early 1910 and sold their entire inventory to Norvell Shapleigh Hardware Co. of St Louis. They rightly saw that the future was with their John M. Browning designed Remington Autoloading Shotgun and their John D. Pedersen designed Remington Repeating Shotgun
Threaded Mode