Uppers
All upper receivers not chambered in 5.56x45 or .223 Remington come with one (1) caliber specific magazine. Capacity may vary depending on your State's laws.
When ordering an upper reciever unit please keep the following in mind: All complete uppers sold on-line come fully assembled, headspaced and test-fired. While each upper is made to mil-spec standards for dimensions and tolerances, uppers may fit differently on various lowers. Some may fit tighter than other, some may fit looser. Some may require minor fitting based on tolerance stacking. Each upper comes with a lifetime warranty and a 60 Day Satisfaction Guaranty. Please see our Warranty page for details.
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16" M4 Tactical Carbine Upper Receiver
K3B-M4-A3-TC-UR16" M4 Tactical Carbine Upper Receiver
Sometimes called the "alphabet gun". The A3-TC variant takes the K3B-M4 and adds a detachable carry handle and FIRSH quad rail free floating handguard. Available in 5.56 NATO Learn More$796.90 -
K45UR: 45 ACP Upper Receiver, 16"
K45-URK45UR: 45 ACP Upper Receiver, 16"
Complete upper receiver assembly manufactured for 45 ACP and includes one 18 round polymer magazine. Standard with A2 upper receiver, but available with an optional picatinny flat-top upper.
Upper is 100% complete with bolt carrier assembly and charging handle. Ready to drop on any standard AR15 lower receiver. Simply attach the upper and swap out to the 45 ACP magazine, and you are ready to shoot. Swap back and forth between calibers in as little as 15 seconds!
This caliber conversion does not require the changing of hammer, trigger, buffers or buffer spring. No need to add in a magazine well adapter or mag well plug either. Designed to work with any standard , unmodified AR15 lower with A2 or collapsible stocks.
Other pistol calibers available: 9mm, 10mm and 40 S&W.
Learn More$721.50 As low as: $701.50 -
K40UR: 16in. 40 S&W Upper Receiver Conversion Unit
K40-URK40UR: 16in. 40 S&W Upper Receiver Conversion Unit
Complete upper receiver assembly manufactured for 40 S&W; and includes one 20 round polymer magazine. Learn More$721.50 -
16in. LT M4 Upper Receiver
LTM4UR16in. LT M4 Upper Receiver
The LT model has a M4 style barrel. Other options are also included standard. Available in 5.56 NATO Learn More$696.80 -
16in. LTF Upper Receiver
LTF UR16in. LTF Upper Receiver
The LTF model has fluting along the full length of the barrel increasing heat dissipation. Other options are also included standard. Available in 5.56 NATO Learn More$743.60 -
K16UR: 16in. K16 Upper Receiver
K16URK16UR: 16in. K16 Upper Receiver
16" Bull barreled match grade 5.56x45 target/hunting upper. Great for an Olympic Arms or any major brand lower. Learn More$533.00 -
K8MAGUR300: 24" .300 OSSM Upper Receiver
K8MAGUR300K8MAGUR300: 24" .300 OSSM Upper Receiver
Upper conversion unit for your complete AR-15 lower receiver designed for the Winchester Super Short Magnum and Olympic Super Short Magnum Learn More$895.70 -
K74UR: 5.45x39 Upper Receiver NEW LOWER PRICE
K74UR -
K9UR-FT: 16" 9mm Flat-top Upper Receiver
K9UR-FTK9UR-FT: 16" 9mm Flat-top Upper Receiver
Complete upper receiver assembly chambered in the wildly popular and affordable 9mm pistol cartridge. Standard forged 7076T6 aluminum Picatinny flat-top upper with one high capacity 30 round polymer magazine. Front sight and handguard options available. Learn More$721.50 As low as: $701.50 -
16" K3B-M4 Upper Receiver
K3B-M4UR16" K3B-M4 Upper Receiver
Features an M4 contoured barrel and M4 handguards. Available in 5.56 NATO Learn More$588.90 -
16" K3B Upper Receiver
K3BUR -
K68UR: 16" 6.8 SPC Upper Receiver
K68URK68UR: 16" 6.8 SPC Upper Receiver
Complete upper receiver assembly manufactured for 6.8 Remington/SPC and includes one magazine. Learn More$637.00 -
K8MAGUR243: 24" .243 WSSM Upper Conversion Receiver Assembly
K8MAGUR243K8MAGUR243: 24" .243 WSSM Upper Conversion Receiver Assembly
Upper conversion unit for your complete AR-15 lower receiver designed for .243 Winchester Super Short Magnum. Learn More$895.70 -
K8MAGUR25: 24" .25 WSSM Upper Conversion Unit"
K8MAGUR25K8MAGUR25: 24" .25 WSSM Upper Conversion Unit"
Upper conversion unit for your complete AR-15 lower receiver designed for .25 Winchester Super Short Magnum. Learn More$895.70 -
K8UR Targetmatch Upper Receiver
K8URK8UR Targetmatch Upper Receiver
Top end assembly with a 20" bull Targetmatch barrel. Available in 5.56 NATO and 6.8 SPC Learn More$560.30 -
K9UR-OR: 9mm Optics Ready Upper Receiver, 16"
K9ur-orK9UR-OR: 9mm Optics Ready Upper Receiver, 16"
K9UR-OR Optics Ready Learn More$767.00 As low as: $747.00 -
K40UR-OR: 40 S&W Optics Ready Upper Receiver, 16"
K40UR-ORK40UR-OR: 40 S&W Optics Ready Upper Receiver, 16"
K40UR-OR Optics Ready Learn More$767.00 As low as: $747.00 -
K45UR-OR: 45 ACP Optics Ready Upper Receiver, 16"
K45UR-ORK45UR-OR: 45 ACP Optics Ready Upper Receiver, 16"
K45UR-OR Optics Ready Learn More$767.00 As low as: $747.00 -
K16-204UR: 16in. .204 Ruger® K16 Style Upper Receiver
K16-204URK16-204UR: 16in. .204 Ruger® K16 Style Upper Receiver
16" Bull barreled match grade .204 Ruger® target/hunting upper. Great for an Olympic Arms or any major brand lower. Learn More$591.50 -
LTFP-6.8UR; 6.8 Remington Upper
LTFP-6.8UR