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Pistol Build Kit (Complete) – 300 Blackout (7.5″ Barrel & 7″ Free Floating Quad Rail) AR 15

$650.00 $550.00 (You Save $100.00)

Pistol Build Kit (Complete) - 300 Blackout (7.5" Barrel & 7" Free Floating Quad Rail) AR 15
Pistol Build Kit (Complete) - 300 Blackout (7.5" Barrel & 7" Free Floating Quad Rail) AR 15
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SKU: UA300PHB7.517(P)-(7)FFQ-BK


For the AR builder who wants an accurate, compact, functional, and lightweight AR pistol build kit in the .300BLK caliber, look no further. Our 7.5″ pistol-length upper assembly features a free float quad rail which provides plenty of picatinny rail space for attachments. With an included bolt carrier group and a standard charging handle, all you need to do is complete the milling and drilling of your 80% lower, assemble the rifle, and you’re good to go.  A 1:7 twist rate and pistol gas system provides a great balance between stabilizing lighter supersonic 300 blackout loads, without sacrificing the ability to reliably shoot heavier subsonic loads.

Mil-Spec Quality and Accuracy

Our 300 blackout pistol upper features a mil-spec 4150 chrome moly steel barrel with M4 feed ramps for guaranteed feeding and reliability. Because our barrels do not use chrome lining, you’ll enjoy superior accuracy, too. Each barrel is heat-treated to a hardness rating of RC 28 to 32 for a stronger rifling that’s more resistant to wear than any other barrel on the market. This negates the need for chrome lining entirely, while still providing superior durability. The upper assembly also features a standard flat Top M4 receiver, housing a quality mil-spec charging handle and chrome-lined bolt carrier group. Everything is manufactured to ISO 9002 quality control standards, ensuring the highest quality upper possible.


Gas System: Pistol-length
Barrel Profile: Standard
Barrel Steel: 4150 Chrome moly vanadium
Barrel Finish: Parkerization
Chrome Lining: No
Muzzle Thread: 5/8×24
Chamber: .300BLK
Twist Rate: 1:7
Barrel Extension: M4
Gas Block Size: .750″
Gas Block Type: Low-profile
Muzzle Device: A2 Flash hider
Receiver Material: Forged 7075 T6
Receiver Type: A4
Handguard Type: 7” quad rail
Bolt Carrier Group Included: Yes
Bolt Steel: 9310 steel, magnetic particle inspected
Bolt Carrier Profile: Full-auto
Charging Handle Included: Yes

Benefits of the 7.5” Pistol-Length Parkerized AR 15 Rifle Kit:

  • 100% legal to own and ship to your front door
  • Not considered a firearm – no FFL paperwork needed!
  • Parkerized 4150 chrome moly vanadium barrel ensures 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: 7.5″ pistol-length parkerized chrome moly vanadium steel, chambered in .300 AAC blackout, 1:7 twist rate, .750″ low-profile gas block, 7″ quad rail handguard, 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

Pistol Build Kit (Complete) – 300 Blackout (7.5″ Barrel & 7″ Free Floating Quad Rail) AR 15

$650.00 $550.00 (You Save $100.00)

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