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300 Blackout AR 15 Rifle Kit (16″ Nitride Barrel & 10″ Quad Rail) w/ 80% Lower

$799.95 $570.00 (You Save $229.95)

Complete Rifle Build Kit - 300 Blackout (16" Barrel, Free Float Quad Rail) AR15
Complete Rifle Build Kit - 300 Blackout (16" Barrel, Free Float Quad Rail) AR15
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SKU: UA300CHB1618(P).750-(10)FFQ_Budget


For the AR builder looking for the perfect combo of quad rail handguard on a rifle chambered in .300BLK, check this out. Our complete .300 AAC blackout rifle build kit features a quality heavy barrel made from 4150 chrome moly steel and carbine-length quad rail picatinny handguard, housing a low-profile, carbine-length gas system. This unique setup allows you to easily switch from supersonic to subsonic loads without the need to swap gas systems or barrels. The simple but proven quad rail offers plenty of space to mount attachments like tac lights, lasers, etc.

Mil-Spec Built, 1-MOA Accuracy on a Budget

Even though our .300 AAC blackout build kit is affordable, it isn’t cheap. The whole thing’s built with mil-spec ratings and features, including a gold-standard 4150 chrome moly barrel that promises 1 MOA of accuracy at 100 yards, M4 feed ramps, M4 flat top upper receiver, A2 birdcage flash hider, and of course, a near replica of the military’s tried and true KAC RAS quad rail system. Unlike the military’s though, our quad rail is free-floating, which provides more accuracy than a fixed handguard.  Plus, everything is made here in the USA to ISO 9002 quality control standards.


Gas System: Carbine-length
Barrel Profile: M4
Barrel Steel: Chrome moly vanadium
Barrel Finish: Black nitride
Chrome Lining: No
Muzzle Thread: 5/8×24
Chamber: .300 AAC Blackout
Twist Rate: 1:8
Barrel Extension: M4
Gas Block Size: .750″
Gas Block Type: Low-profile
Muzzle Device: A2 Flash hider
Receiver Material: Forged 7075 T6
Receiver Type: M4
Handguard Type: Free-float quad rail
Bolt Carrier Group Included: Yes
Bolt Steel: 9310 steel, magnetic particle inspected
Bolt Carrier Profile: Full-auto
Charging Handle Included: Yes
Overall Length: 24.5″

Benefits of the 16” Carbine-Length Black-Barreled AR 15 Rifle Kit:

  • 100% legal to own and ship to your front door
  • Not considered a firearm – no FFL paperwork needed!
  • Chrome moly vanadium steel barrel and Freedom parts kit ensure sub-MOA accuracy
  • Prebuilt upper with gas system removes the guesswork of rifle making
  • Includes bolt carrier group, free-floated M-Lok handguard and lower parts kit

AR 15 Rifle Kit Details (Expanded):

Barrel: 16″ carbine-length with black nitride finish, chambered in .300BLK, 1:8 twist rate, .750″ low-profile gas block, free-float quad rail, with an A2 “birdcage” flash hider.

Upper Receiver Assembly: Forged from 7075 T6 aluminum, hard-coat anodized in black for durability, features M4 feed ramps, and are made in the USA.

Bolt Carrier Group: The bolt carrier is made from 9310 steel and has a staked gas key and black nitride finish. The bolt itself comes complete with an extractor spring and O-ring insert.  It accepts .223 Wylde, 5.56mm, and .300BLK calibers (though you should NEVER attempt to use a caliber for which your rifle is not chambered), and is magnetic particle inspected.

80% Lower Receiver: Choose to receive a forged or billet Fire/Safe 80% lower receiver.  Our lower receivers are anodized to match the upper receiver perfectly. and they come ready for machining of the trigger pocket and drilling of the safety selector and trigger pin holes.

AR-15 Lower Parts Kit: includes all parts needed to complete the lower receiver including pistol grip, mil-spec safety selector, and trigger/fire control group.

Lower Assembly: comes with complete buffer tube assembly including buffer, buffer spring, six-position buffer tube, latch plate, castle nut, and butt stock based on original Colt design.

Charging Handle: standard size, made from 6061 aluminum.

Please note: This build kit requires that the builder complete the 80% lower receiver themselves, but that’s the rewarding part of the experience (and the only way to build your own AR-15 without the need of an FFL transfer or serialization).

No FFL required Made in the USA Lifetime Warranty

300 Blackout AR 15 Rifle Kit (16″ Nitride Barrel & 10″ Quad Rail) w/ 80% Lower

$799.95 $570.00 (You Save $229.95)

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$799.95 $520.00 (You Save $279.95 )
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