A concentric rifle barrel assembly includes an outer sleeve having a plurality of threads along the first and second ends, an elongated rifle barrel, and a locking nut. The first end of the rifle barrel is removably positioned within the sleeve and includes a chamber that is sized to receive a firearm cartridge. Threads on the locking nut engage the second end of the sleeve, and a positioning ring that is located a first distance from the first end of the rifle barrel. The first distance being complementary to the length of the sleeve minus the length of the rim of the firearm cartridge for which the barrel is designed to accommodate. Fluting is provided along one or both of the rifle barrel and the sleeve, and the sleeve is designed to receive any number of different rifle barrels each sized to accommodate cartridges of different sizes and calibers.