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MCS

CAA

Presma

Trinity Force

JE Machine tech

XTS

LUTH-AR

Armaspec

Northtac

Rise Armament

Sylvan Arms

Bushnell

CMC Triggers

LBE Unlimited

Sig Sauer

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Timney Triggers

UTG Leapers

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Mcs has a great selection of AR Build Kits. We have low cost kits starting under $79 and premium kits at competitive prices. All Backed by our satisfaction guarantee.

AR-15 Pistol Upper, .223 Wylde, 7.5'' Barrel, 1:7 Twist, Pistol Gas System

MSRP: $399.99

Was: $349.99

Now: $299.99

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AR-15 300 blackout 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

MSRP: $570.99 - $580.99

Was:

Now: $490.99 - $510.99

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5" 7.62X39 COMPLETE UPPER ASSEMBLY WITH BCG (BUILT)

MSRP: $399.99

Was: $359.99

Now: $349.99

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5" 5.56 NATO PISTOL KIT W/ 3.5" SHORT BUFFER SYSTEM

MSRP: $589.99

Was: $529.99

Now: $469.99

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Sylvan Arms Conversion Block For Glock

MSRP: $120.99

Was: $110.99

Now: $99.99

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AR-15 Upper Receiver, .223 Wylde, 16'' Barrel, 1:8 Twist, Carbine Gas System

MSRP: $419.99

Was: $399.99

Now: $315.99

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AR-15 5.56 Nato 7.5″ Pistol Upper Complete Build Kits Assembled Black barrel Upper

MSRP: $550.99 - $560.99

Was:

Now: $470.99 - $490.99

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AR-15 Complete Upper Receiver Assembly (USA) w/Forward Assist, Dust Cover & Charging Handle

MSRP: $110.99

Was: $99.99

Now: $80.99

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AR-15 7.62×39 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

MSRP: $580.99 - $590.99

Was:

Now: $490.99 - $510.99

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AR-15 5.56 Nato 10.5″ Pistol Upper Complete Build Kits Assembled Black barrel Upper

MSRP: $560.99 - $570.99

Was:

Now: $485.99 - $500.99

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AR-15 .223 Wylde 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

MSRP: $579.99 - $589.99

Was:

Now: $489.99 - $505.99

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AR-15 5.56 Nato 10.5″ Pistol Upper Complete Build Kits Assembled S.S barrel Upper

MSRP: $599.99 - $605.99

Was:

Now: $520.99 - $530.99

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AR-15 Pistol Upper, .223 Wylde, 7.5'' Barrel, 1:7 Twist, Pistol Gas System

Model: MCS AR-15 Pistol Upper, .223 Wylde, 7.5'' Barrel, 1:7 Twist, Pistol Gas System Unique Characteristics: This .223 Wylde AR-15 Pistol Upper receiver, assembled by MCS, is one of our options for an AR-15 Assembled Upper receiver. Our specialty is...

MSRP: $399.99

Was: $349.99

Now: $299.99

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AR-15 300 blackout 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

MCS is now proud to offer the AR15 Assembled Rifle Build Kit. With this build kit, you will be able to have almost all of the necessary components to build your very own AR-15 Rifle ! AR15 Assembled Rifle Upper Receiver Components: A fully assembled...

MSRP: $570.99 - $580.99

Was:

Now: $490.99 - $510.99

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5" 7.62X39 COMPLETE UPPER ASSEMBLY WITH BCG (BUILT)

(BUILT) USA Made 5" 7.62x39 COMPLETE UPPER ASSEMBLY Our USA Made Upper assemblie is one of our many options for an AR-15 Assembled Upper receiver. Our specialty is designing custom built upper receiver that only use the best USA Made parts at the best...

MSRP: $399.99

Was: $359.99

Now: $349.99

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5" 5.56 NATO PISTOL KIT W/ 3.5" SHORT BUFFER SYSTEM

MCS Unassembled Pistol Build Kit The Build Kit Includes: (1) 5.5" 5.56 barrel, 1:5 twist, Micro Gas system,1/2-28 muzzle thread, nitride finish 5.56 upper receiver with M4 feedramps (1) 5.56 Bolt Carrier Group Low profile adjustable gas...

MSRP: $589.99

Was: $529.99

Now: $469.99

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Sylvan Arms Conversion Block For Glock

Sylvan Arms Conversion Block Black Easily converts Standard AR-15 lowers to use with glock 9 mm uppers. Be sure to have your 9 mm barrel and bolt carrier group installed before using. This product is back by the Sylvan Arms Limited lifetime warranty.

MSRP: $120.99

Was: $110.99

Now: $99.99

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AR-15 Upper Receiver, .223 Wylde, 16'' Barrel, 1:8 Twist, Carbine Gas System

Model: MCS AR-15 Upper Receiver, .223 Wylde, 16'' Barrel, 1:8 Twist, Carbine Gas System Unique Characteristics: This .223 Wylde AR-15 Upper receiver, assembled by MCS, is one of our options for an AR-15 Assembled Upper receiver. Our specialty is...

MSRP: $419.99

Was: $399.99

Now: $315.99

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AR-15 5.56 Nato 7.5″ Pistol Upper Complete Build Kits Assembled Black barrel Upper

MCS is now proud to offer the AR-15 Assembled Pistol Build Kit. With this build kit, you will be able to have almost all of the necessary components to build your very own AR-15 Pistol ! AR-15 Assembled Pistol Upper Receiver Components: A fully...

MSRP: $550.99 - $560.99

Was:

Now: $470.99 - $490.99

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AR-15 Complete Upper Receiver Assembly (USA) w/Forward Assist, Dust Cover & Charging Handle

Lightweight Upper Receiver is made of 7075-T6 Forged Aluminum. Made in the U.S.A. This kit includes our standard Ejection Port Cover and Forward Assist Kit. (Assembled & No BCG) Features: Upper: 7075-T6 Forged Aluminum Black...

MSRP: $110.99

Was: $99.99

Now: $80.99

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AR-15 7.62×39 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

MCS is now proud to offer the AR15 Assembled Rifle Build Kit. With this build kit, you will be able to have almost all of the necessary components to build your very own AR-15 Rifle ! AR15 Assembled Rifle Upper Receiver Components: A fully assembled...

MSRP: $580.99 - $590.99

Was:

Now: $490.99 - $510.99

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AR-15 5.56 Nato 10.5″ Pistol Upper Complete Build Kits Assembled Black barrel Upper

MCS is now proud to offer the AR-15 Assembled Pistol Build Kit. With this build kit, you will be able to have almost all of the necessary components to build your very own AR-15 Pistol. AR-15 Assembled Pistol Upper Receiver Components: A fully assembled...

MSRP: $560.99 - $570.99

Was:

Now: $485.99 - $500.99

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AR-15 .223 Wylde 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

MCS is now proud to offer the AR15 Assembled Rifle Build Kit. With this build kit, you will be able to have almost all of the necessary components to build your very own AR-15 Rifle ! AR15 Assembled Rifle Upper Receiver Components: A fully assembled...

MSRP: $579.99 - $589.99

Was:

Now: $489.99 - $505.99

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AR-15 5.56 Nato 10.5″ Pistol Upper Complete Build Kits Assembled S.S barrel Upper

MCS is now proud to offer the AR-15 Assembled Pistol Build Kit. With this build kit, you will be able to have almost all of the necessary components to build your very own AR-15 Pistol ! AR-15 Assembled Pistol Upper Receiver Components: A fully...

MSRP: $599.99 - $605.99

Was:

Now: $520.99 - $530.99

Choose Options Compare

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AR-15 Pistol Upper, .223 Wylde, 7.5'' Barrel, 1:7 Twist, Pistol Gas System

AR-15 300 blackout 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

5" 7.62X39 COMPLETE UPPER ASSEMBLY WITH BCG (BUILT)

5" 5.56 NATO PISTOL KIT W/ 3.5" SHORT BUFFER SYSTEM

Sylvan Arms Conversion Block For Glock

AR-15 Upper Receiver, .223 Wylde, 16'' Barrel, 1:8 Twist, Carbine Gas System

AR-15 5.56 Nato 7.5″ Pistol Upper Complete Build Kits Assembled Black barrel Upper

AR-15 Complete Upper Receiver Assembly (USA) w/Forward Assist, Dust Cover & Charging Handle

AR-15 7.62×39 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

AR-15 5.56 Nato 10.5″ Pistol Upper Complete Build Kits Assembled Black barrel Upper

AR-15 .223 Wylde 16″ Rifle Upper Complete Build Kits Assembled Black barrel Upper

AR-15 5.56 Nato 10.5″ Pistol Upper Complete Build Kits Assembled S.S barrel Upper