A heat protective sleeve includes a body being cylindrical extending along a longitudinal direction and comprising a triply periodic minimal surfaces (TPMS) structure, an open cell foam structure, or a lattice structure. A strip extends along the longitudinal direction of the body. The strip is a same material as the TPMS structure, the open cell foam structure, or the lattice structure. The material of the strip is solid and without holes through it. An endcap removably couples to the body. In some examples, the body has fastening threads and the endcap has mating threads. The mating threads of the endcap are configured to engage with the fastening threads of the body to releasably couple the endcap to the body.

A heat protective sleeve includes a body being cylindrical extending along a longitudinal direction and comprising a triply periodic minimal surfaces (TPMS) structure, an open cell foam structure, or a lattice structure. A strip extends along the longitudinal direction of the body. The strip is a same material as the TPMS structure, the open cell foam structure, or the lattice structure. The material of the strip is solid and without holes through it. An endcap removably couples to the body. In some examples, the body has fastening threads and the endcap has mating threads. The mating threads of the endcap are configured to engage with the fastening threads of the body to releasably couple the endcap to the body.

A firearm barrel with non-metal outer sleeve preferably includes an elongated tube, a first non-metal tube, a second non-metal tube, a sleeve nut and a coupler bushing. A first raised sleeve support section and a raised coupler section are formed on the elongated sleeve. The raised coupler section is formed in substantially a middle of the elongated tube. The bushing inner diameter is sized to slidably receive an outer diameter of the raised coupler section. The first and second non-metal tubes include a tube inner diameter and a plurality of openings formed through a wall thereof. The tube inner diameters are sized to slidably receive an outer diameter of the first raised sleeve support section and each end of the coupler bushing. The sleeve nut retains the first and second non-metal tubes and the coupler bushing on the elongated tube. A second embodiment includes a single non-metal tube.

A firearm barrel with non-metal outer sleeve preferably includes an elongated tube, a first non-metal tube, a second non-metal tube, a sleeve nut and a coupler bushing. A first raised sleeve support section and a raised coupler section are formed on the elongated sleeve. The raised coupler section is formed in substantially a middle of the elongated tube. The bushing inner diameter is sized to slidably receive an outer diameter of the raised coupler section. The first and second non-metal tubes include a tube inner diameter and a plurality of openings formed through a wall thereof. The tube inner diameters are sized to slidably receive an outer diameter of the first raised sleeve support section and each end of the coupler bushing. The sleeve nut retains the first and second non-metal tubes and the coupler bushing on the elongated tube. A second embodiment includes a single non-metal tube.

A gun barrel assembly includes an outer barrel tube, an inner barrel liner, a barrel breech cap and a barrel muzzle cap. The barrel tube and the barrel liner each longitudinally extend from a muzzle end to a breech end, and have axial through bores, with the barrel liner being disposed within and coaxial with the barrel tube bore. The breech cap and the muzzle cap each longitudinally extend from a front end to a rear end and have through axial through bores. The breech cap is mounted to the barrel liner breech end portion and contacts the barrel tube breech end. The muzzle cap is mounted to the barrel liner muzzle end portion and contacts the barrel tube muzzle end. The inside diameter of the barrel tube bore is greater than the outside diameter of the barrel liner whereby the barrel tube does not contact the barrel liner.

A gun barrel assembly includes an outer barrel tube, an inner barrel liner, a barrel breech cap and a barrel muzzle cap. The barrel tube and the barrel liner each longitudinally extend from a muzzle end to a breech end, and have axial through bores, with the barrel liner being disposed within and coaxial with the barrel tube bore. The breech cap and the muzzle cap each longitudinally extend from a front end to a rear end and have through axial through bores. The breech cap is mounted to the barrel liner breech end portion and contacts the barrel tube breech end. The muzzle cap is mounted to the barrel liner muzzle end portion and contacts the barrel tube muzzle end. The inside diameter of the barrel tube bore is greater than the outside diameter of the barrel liner whereby the barrel tube does not contact the barrel liner.

Disclosed are examples of an apparatus for cooling a barrel 12 of a firearm 10 and examples of a cooled barrel assembly 32 for installation into an existing firearm 10. When assembled with the barrel 12, a contact surface 16 of a shell 14 is proximate to, and in thermal communication with, the outer surface of the barrel 18. The shell 14 is formed of commercially available or modified graphite foam.

Disclosed are examples of an apparatus for cooling a barrel 12 of a firearm 10 and examples of a cooled barrel assembly 32 for installation into an existing firearm 10. When assembled with the barrel 12, a contact surface 16 of a shell 14 is proximate to, and in thermal communication with, the outer surface of the barrel 18. The shell 14 is formed of commercially available or modified graphite foam.

An upper receiver assembly includes a barrel, a suppressor body operable to couple to a muzzle end of the barrel, and a first sleeve disposable about the barrel and the suppressor body, wherein the barrel includes one or more longitudinally oriented ribs extending radially from a barrel body having a bore formed therein, and a second sleeve surrounding the first sleeve, the second sleeve comprising a fibrous thermally insulating material.

An upper receiver assembly includes a barrel, a suppressor body operable to couple to a muzzle end of the barrel, and a first sleeve disposable about the barrel and the suppressor body, wherein the barrel includes one or more longitudinally oriented ribs extending radially from a barrel body having a bore formed therein, and a second sleeve surrounding the first sleeve, the second sleeve comprising a fibrous thermally insulating material.