Patent ID: 7444775
Filing Date: 2008-11-04
Classification: F41A

Abstract:
1. A caliber convertible, upper receiver system for a magazine-equipped, manually operated or semiautomatic or fully automatic firearm, said upper receiver system being adapted to replace the original equipment upper receiver portion and to attach to the original equipment lower receiver portion of said firearm in order to render the firearm capable of firing either a first cartridge or a second cartridge, the first and second cartridges having dissimilar calibers, the system comprising: an upper receiver assembly attachable to the lower receiver portion of the firearm, said assembly including a barrel assembly extending longitudinally from a rear, firing chamber end to an opposite, front end, said barrel assembly including a first barrel liner dimensioned for insertion into the barrel bore and to receive at a rear, firing chamber end thereof a bullet fired from the first cartridge in the firing chamber, and to conduct the bullet through the barrel assembly and out an opposite, front end of said barrel liner, said first barrel liner including a second barrel liner dimensioned for insertion into the barrel bore and to receive at a rear, firing chamber end thereof a bullet fired from the second cartridge in the firing chamber, and to conduct the bullet through the barrel assembly and out an opposite, front end of said barrel liner, said second barrel liner including a bolt adapter carrier assembly insertable into the cylindrical interior space of the lower receiver, said assembly including a bolt that carries a spring-loaded firing pin mounted for reciprocal, longitudinal movement within a firing pin bore of the bolt, and means for attaching and disattaching alternately the head of either the first or the second barrel liner to said carrier assembly; and a magazine adapter insert dimensioned for insertion and retention within the magazine of the firearm and adapted to receive and store a plurality of the first or second cartridges for use as ammunition by the firearm.