Lifetime Warranty Lifetime Warranty Made in the USA Made in the USA FREE Shipping on $325+ Free Shipping on all orders $325+!

What Is a 300 Blackout Upper

Great question! It’s a fitting, given the introduction of our new website. To answer that question, let’s dive into a brief history of the 300 Blackout, and how it came to be. In 1990, firearms community veteran J.D. Jones developed the 300 Whisper in his garage. He intended it to be a suppressor-friendly, intermediate rifle cartridge that packed enough punch and hit far enough to make a good hunting cartridge.

He was successful, and when the military caught wind of the round, they found a solution to their own need. That need was the development of a compact short-barreled rifle that could shoot supersonic and subsonic munitions with 7.62x39mm-like ballistic. The 300 Whisper was refined by Advanced Armament Corp. and received SAAMI certification, officially titled 300 AAC Blackout, or 300 BLK.

So, with the cartridge’s intent known, what does that mean for all these 300 Blackout Uppers? Why do you want one? Let’s break down each upper configuration: Rifle-length, SBR-length, and pistol-length.

A 300 Blackout Upper is (Mostly) a Standard AR 15 Upper

We wrote an entire article comparing the two platforms, but in a sweet and simple summary, 300 Blackout uppers are basically exactly like .223 or 5.56 AR 15 uppers, save for the .30-caliber barrel change. All other components are the same, in case you were wondering. So mechanically, a 300 Blackout upper is like any other good ole’ AR 15 when it comes to mechanics and looks.

Why a 300 Blackout Rifle Upper?

The 300 Blackout Rifle Upper is the easiest way to enjoy all the benefits of this whisper round, without having to pay for two tax stamps. We’re referring to having to shell out $200 for a suppressor stamp, and another $200 for an SBR stamp. At 16”, a rifle-length 300 Blackout Upper offers superior velocity and stabilization, allowing a shooter to reach 460 meters with 125-grain factory loads.

300 Blackout Upper (16” Barrel & M-Lok Handguard) AR15 Complete Rifle Upper


With hand-loaded 110 grain Barnes bullets, you can expect to reach a whopping 650 meters on a good day with a light wind. That’s nearing what most shooters can handle with a 308 upper. What’s better, those rifle-length uppers can still shoot subsonic rounds with high accuracy, suppressed or unsuppressed. In effect, if you want the quietest AR 15 rifle possible, a 300 Blackout Upper’s what you want.

Why a 300 Blackout Pistol Upper?

The 300 Blackout truly shines (and outshines most other black rifle rounds) when it’s put through an SBR or pistol upper. The military intended for the 300 Blackout to be chambered in a 10.5” SBR, outfitted with a suppressor. You can enjoy the same configuration by biting the bullet and paying for those two ATF tax stamps. Trust us, it’s worth it.

5.56 NATO (10.5" Barrel & MOE Handguard) AR 15 Pistol Upper

A 10.5” 300 Blackout Upper will afford you one of the most compact, hard-hitting, accurate AR 15 uppers available on the market. The same applies to our pistol uppers that are found with 7” to 8” barrels – they’ll provide you with an even more compact SBR or pistol, making them perfect for home defense. These uppers will hit with more energy than any sub gun, while offering even more accuracy than the aforementioned, too.

Why You’d Want Either One

So, if you’re looking for an easy-to-shoot, versatile, quiet AR 15 upper that can simultaneously reach out a few hundred meters, pack more punch than a .223 or 5.56, and be suppressed with more accuracy and energy than a sub gun, a 300 Blackout Upper should be your next investment.


Get exclusive discounts on AR-15 gear and be the first to know about new product releases.

100% Satisfaction

Customer Service is our passion and we are here to answer any questions you have.

Shop With PRIDE

Shop With Confidence

Secure Payment

Left Menu IconMENU
Right Menu Icon