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Kak Industry
The KAK Industry K-Spec 5.56 NATO 14.5" complete upper is a no-nonsense, American-made rifle upper built for shooters who want reliability and performance without compromise. This is a ready-to-mount upper receiver paired with everything you need—barrel, bolt carrier group, handguard, and muzzle device—so you can build or upgrade an AR platform rifle without sourcing parts separately. The 14.5" barrel length hits a practical balance between handling and velocity for 5.56 NATO rounds, while the 1:7 twist rate stabilizes a wide range of bullet weights from lighter target loads to heavier hunting and defense ammunition.
Build quality here is solid: the upper itself is forged 7075 T6 aluminum, the barrel is 4150 CrMoV steel with a chrome-lined bore and chamber (easier to clean, longer lasting), and it's stress-relieved twice to minimize warping. The mid-length gas system is a proven platform that keeps recoil and wear manageable. The included K-SPEC Enhanced bolt carrier group uses a chrome-lined phosphate finish and features a down-vent design—gas vents redirect exhaust downward instead of straight into your face, a real advantage if you're running a suppressor with a baffle can. The 13" MLOK handguard is free-floated and comes with a heavy-duty barrel nut, giving you a rock-solid mounting platform for optics, lights, or other accessories. The Brownells-exclusive PentaComp muzzle device (1/2x28 threads) is included. Every upper ships test-fired.
Whether you're building a new rifle, upgrading an upper, or looking for a suppressor-ready platform, this complete upper cuts out the guesswork and gets you behind quality hardware fast.
| Caliber | 5.56 NATO |
| Barrel Length | 14.5" |
| Barrel Material | 4150 CrMoV, chrome-lined |
| Twist Rate | 1:7" |
| Upper Receiver | Forged 7075 T6 aluminum |
| Gas System | Mid-length |
| Bolt Carrier Group | K-SPEC Enhanced, chrome-lined phosphate, down-vent design |
| Handguard | 13" MLOK, free-floated, heavy-duty barrel nut |
| Muzzle Device | Brownells PentaComp, 1/2x28 threads |
| Charging Handle | Large billet latch enhanced |
| Finish | Black |
| Country of Origin | USA |
This is a complete upper receiver assembly designed for standard AR-platform lowers. You'll need a mil-spec or commercial AR lower to complete the rifle. It should mount on any standard AR lower receiver.
Yes. The K-SPEC down-vent bolt carrier group is specifically engineered to work well with suppressors, redirecting gas downward away from your face. The muzzle device is 1/2x28 threaded, the standard for 5.56 NATO, so it accepts any suppressor with that thread pitch.
The upper ships fully assembled with the barrel, bolt carrier group, charging handle, handguard, and PentaComp muzzle device all installed. You only need to mount it on a lower receiver to have a complete rifle.
Yes, the barrel has a chrome-lined bore and chamber. Chrome-lining makes the bore easier to clean and helps it resist corrosion and heat, extending barrel life—a real advantage if you shoot suppressed or in high round-count sessions.
Kak Industry
The KAK Industry K-Spec 5.56 NATO 14.5" complete upper is a no-nonsense, American-made rifle upper built for shooters who want reliability and performance without compromise. This is a ready-to-mount upper receiver paired with everything you need—barrel, bolt carrier group, handguard, and muzzle device—so you can build or upgrade an AR platform rifle without sourcing parts separately. The 14.5" barrel length hits a practical balance between handling and velocity for 5.56 NATO rounds, while the 1:7 twist rate stabilizes a wide range of bullet weights from lighter target loads to heavier hunting and defense ammunition.
Build quality here is solid: the upper itself is forged 7075 T6 aluminum, the barrel is 4150 CrMoV steel with a chrome-lined bore and chamber (easier to clean, longer lasting), and it's stress-relieved twice to minimize warping. The mid-length gas system is a proven platform that keeps recoil and wear manageable. The included K-SPEC Enhanced bolt carrier group uses a chrome-lined phosphate finish and features a down-vent design—gas vents redirect exhaust downward instead of straight into your face, a real advantage if you're running a suppressor with a baffle can. The 13" MLOK handguard is free-floated and comes with a heavy-duty barrel nut, giving you a rock-solid mounting platform for optics, lights, or other accessories. The Brownells-exclusive PentaComp muzzle device (1/2x28 threads) is included. Every upper ships test-fired.
Whether you're building a new rifle, upgrading an upper, or looking for a suppressor-ready platform, this complete upper cuts out the guesswork and gets you behind quality hardware fast.
| Caliber | 5.56 NATO |
| Barrel Length | 14.5" |
| Barrel Material | 4150 CrMoV, chrome-lined |
| Twist Rate | 1:7" |
| Upper Receiver | Forged 7075 T6 aluminum |
| Gas System | Mid-length |
| Bolt Carrier Group | K-SPEC Enhanced, chrome-lined phosphate, down-vent design |
| Handguard | 13" MLOK, free-floated, heavy-duty barrel nut |
| Muzzle Device | Brownells PentaComp, 1/2x28 threads |
| Charging Handle | Large billet latch enhanced |
| Finish | Black |
| Country of Origin | USA |
This is a complete upper receiver assembly designed for standard AR-platform lowers. You'll need a mil-spec or commercial AR lower to complete the rifle. It should mount on any standard AR lower receiver.
Yes. The K-SPEC down-vent bolt carrier group is specifically engineered to work well with suppressors, redirecting gas downward away from your face. The muzzle device is 1/2x28 threaded, the standard for 5.56 NATO, so it accepts any suppressor with that thread pitch.
The upper ships fully assembled with the barrel, bolt carrier group, charging handle, handguard, and PentaComp muzzle device all installed. You only need to mount it on a lower receiver to have a complete rifle.
Yes, the barrel has a chrome-lined bore and chamber. Chrome-lining makes the bore easier to clean and helps it resist corrosion and heat, extending barrel life—a real advantage if you shoot suppressed or in high round-count sessions.
