Sale

AR-15 300 Blackout 16" Rifle Upper Complete Build Kits (Unassembled Black Barrel Upper) - Black

Shooters Gate
SKU:
AR-BDKT-U300-16P8HP-M15-BLK
$475.99 $259.19
(4 reviews)
Weight:
7.00 LBS
Current Stock:
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Builders Tried Everything. This One Worked.

AR Build Kit Review

“Ordered the kit and had it in two days. Built it using a ShootersGate lower — everything fit the way it should. Put about 200 rounds through it with zero malfunctions. Solid kit, no shortcuts taken. I’d recommend it without hesitation.”

★★★★★
Michael T. Verified Builder
AR Build Kit Review

“This was my first build, and it went together pretty easily thanks to the step-by-step guidance provided on the ShootersGate website.”

★★★★★
James R. Verified Builder
AR Build Kit Review

“Best value for the money. Easy to assemble and far better organized than many other kits I’ve worked with. Lightweight, nicely balanced, and feels great once everything is together.”

★★★★★
David L. Verified Builder
AR Build Kit Review

“Bought this for my first AR build and have to say it’s a great kit for the price. I was honestly surprised by how good it looks and how smoothly everything went together. They even included some helpful extras — a sling, a gun mat, and an armorer’s wrench.”

★★★★★
Daniel S. Verified Builder
AR Build Kit Review

“Overall, a really good experience. Shipping was fast and everything showed up as expected. I had a quick question for customer service and they were easy to deal with. I’d buy from ShootersGate again and would recommend them to friends.”

★★★★★
Mark W. Verified Builder
AR Build Kit Review

“This works great. Seems to be good quality and all of the pieces fit perfectly.”

★★★★★
Brian K. Verified Builder
AR Build Kit Review

“Great product. Fast shipping. Everything fit together with ease. Fired beautifully at the range. Very happy with my purchase. Price was extremely reasonable.”

★★★★★
Kevin M. Verified Builder
AR Build Kit Review

“Great kit — first time building an AR-15. Went together easy and shoots good.”

★★★★★
Steven C. Verified Builder
AR Build Kit Review

“This was my first kit, and assembly was very easy. Everything came neatly organized in separate bags, which made the process straightforward. I’d definitely recommend it to anyone considering one.”

★★★★★
Thomas J. Verified Builder
AR Build Kit Review

“Great rifle at a great price. Shipped extremely fast and no problems assembling.”

★★★★★
Anthony P. Verified Builder
AR Build Kit Review

“Everything was as described. Fit and finish was perfect. Easy to install.”

★★★★★
Verdell M. Verified Builder
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7.5” vs 10.5” vs 16” .300 Blackout Uppers

Choosing between a 7.5”, 10.5”, or 16” .300 Blackout upper depends on your intended application. While shorter barrels prioritize compact pistol builds, the 16 inch barrel is designed for rifle-length setups emphasizing velocity, control, and extended range.

Barrel Length Best Use Advantages Considerations
7.5” Ultra-compact pistol builds Extremely compact, ideal for close-quarters handling Reduced velocity, louder muzzle blast
10.5” Balanced pistol configuration Better velocity than 7.5”, still compact and maneuverable Longer than ultra-short setups
16” Rifle-length builds Highest velocity, improved accuracy potential, smoother recoil impulse Longer overall length, less compact than pistol setups

Key Features

Upper Receiver Black Forged 7075-T6 Mil-Spec Stripped upper receiver
16" 300 Blackout Barrel 16'' 300 Blackout barrel
Dust Cover & Forward Assist Black dust cover
Black forward assist
Gas System Gas Block.750
Carbine Gas Tube
Handguard 15’’ Black M-LOK Free Float Handguard
BCG & Charging Handle Bolt carrier group, made in the USA
Black standard charging handle
Twist Ratios 300 Blackout Barrels are 1:8 Twist, Carbine Gas System

What You Still Need to Complete the Build

Stripped Lower Receiver You will still need an AR-15 Stripped Lower Receiver (FFL & Background Check required)
Magazine You will also need a magazine that is suitable for your desired caliber.

Package Contents

A fully unassembled Upper with the following components:
Black Forged 7075-T6 Mil-Spec Stripped upper receiver
16'' 300 Blackout barrel
Black dust cover
Black forward assist
Gas Block.750
Carbine Gas Tube
A2 Bird Cage Flash Hider with crush washer.
15’’ Black M-LOK Free Float Handguard
Bolt carrier group, made in the USA
Black standard charging handle
Black lower parts kit
Black Mil-Spec Buffer Tube (Commercial set available on request)
Black castle nut
Black end plate with 
Black Mil-spec Stock with built in sling adapter (Commercial set available on request)
Buffer Spring
Buffer
Extra Ambi end plate
Armor Wrench
Gun mat
One point sling

Model: AR-15 Unassembled Rifle Build Kit

Shooters Gate is now proud to offer the AR-15 Unassembled 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!

FAQ

Is a 16 inch barrel good for .300 Blackout?
Yes. A 16” .300 Blackout barrel maximizes velocity and offers improved control and consistency. It is well suited for rifle builds where size is less critical than performance and shootability.
Why choose a 16” upper instead of 7.5” or 10.5”?
A 16” upper provides higher velocity, smoother recoil characteristics, and improved effective range compared to shorter barrels. It is ideal for shooters who prefer a rifle-length setup over compact pistol builds.
Is this upper fully assembled?
No. This is an unassembled upper build kit. It allows builders to assemble components according to their preferences. Professional assembly is recommended.
Is this upper compatible with AR rifle builds?
Yes. A 16” .300 Blackout upper is designed for standard AR rifle configurations. Compatibility depends on your lower receiver and overall build setup.
Can this .300 Blackout upper be used for suppressed shooting?
.300 Blackout is commonly used in suppressed configurations. Suitability depends on your suppressor, gas system, and tuning. Always follow applicable laws and regulations.

Reviews

  • 5
    Perfect

    Posted by Chris on Jan 4th 2026

    I bought this kit back in October and I ran 500 rounds through it without a hiccup

  • 5
    Great

    Posted by Thomas on Jan 4th 2026

    Great shipping, great service these guys are fabulous. ordered my first build , and just ordered another for the wife, our son just ordered one.

  • 5
    Perfect

    Posted by Matthew on Jan 4th 2026

    Great site. Exactly what I’m looking for.

  • 5
    Awesome price

    Posted by Rudy on Dec 17th 2025

    Great product and all parts very durable. Awesome price and highly recommended!