Lots of 300 Blackout uppers are available, and they all serve their own purpose – so which is best for you? With so many options available, and with the idea that 300 Blackout is such a multi-purpose, multi-load cartridge, let’s break down the top 5 300 Blackout Uppers, and why you might want a particular one. To clarify, this is a “best-to-worse” breakdown, we’re simply identifying the best uppers that serve a particular purpose. That could be long-range shooting, building a compact rifle, building the most affordable 300 Blackout AR 15, building an SBR, or building the most accurate 300 Blackout pistol. Let’s get started:
- 300 Blackout (16” Barrel & 15” Lightweight Keymod Handguard) AR 15 Complete Rifle Upper
First up is what we consider to be our best all-around performer, a 16”, 4150 Chromoly barrel and a 15” lightweight handguard combo for plenty accuracy, rail estate, and weight savings. This upper features just enough barrel length with heat-treated rifling and a heavy profile to reliably (and accurately) cycle supersonic and subsonic loads.
We often see 1 MOA groups at 100 yards with this setup in both loads. A 1:8 twist rate handles both loads reliably, and a 5/8 x 24 thread pitch makes suppression easy. The carbine gas system contributes to that all-around reliability shooting either load, and the lightweight Keymod handguard makes maneuvering and carrying comfortable. At 15”, this is our longest handguard we offer, too.
- 300 Blackout (16” Barrel, Carbine-Length, A2 Handguard) AR 15 Complete Rifle Upper
Simply put, this upper offers that guaranteed 1 MOA accuracy you want in a premium upper while keeping things simple and costs to a minimum. You’re still getting that laser beaming 16”, 4150 Chromoly barrel with a heavy profile and heat treatment, but the classic A2 handguard and A2 birdcage flash hider make no bones about providing simple functionality.
A carbine gas system and chrome-lined BCG still ensure you can reliably cycle supersonic and subsonic loads suppressed or unsuppressed. This upper is a great way to get into the 300 Blackout game without spending an arm and leg. You can easily upgrade this upper over time, but it’ll be enjoyable and easy to shoot right out of the box.
- 300 Blackout Upper (16” Barrel, Carbine-Length, Quad Rail) AR 15 Complete Rifle Upper
If you’re the guy (or gal) who wants to build the most rugged, beefed up and USGI-like 300 Blackout AR 15, our 16” barreled, quad rail-equipped upper is for you. Featuring USGI Picatinny rails, this upper provides arguably the most attachment options in a carbine configuration. The tough-as-nails Picatinny attachment method is the most universal and battle-proven way to secure sights, optics, handguards, or any other accessories.
Like many of our top-tier uppers, this 16” barrel features a heavy profile with heat treated rifling for superior barrel life, strength, and MOA accuracy. A nominal 1:8 twist rate ensures reliable, accurate shooting with supersonic or subsonic loads, and the carbine gas system provides guaranteed function shooting suppressed or unsuppressed. This upper is one of our more affordable options, making it a great way to enjoy a bomb-proof, proven design without breaking the bank.
- 300 Blackout (10.5” SS Barrel & 10” M-Lok Handguard) AR 15 Complete Pistol Upper
If you’re looking to build the shortest yet still most accurate AR 15 that truly provides everything the 300 Blackout cartridge was meant to offer, our 10.5” stainless pistol upper should be your number one choice. Configured with the barrel length and M-Lok handguard that the special warfare community prefers, this upper makes the perfect starting point for building the most accurate 300 Blackout SBR or pistol possible.
Expert shooters who handle 300 Blackout agree the 10.5” barrel length provides the optimal combination of compactness, weight savings, and accuracy. Our 416R stainless steel barrel kicks up that last factor a notch to easily provide sub-MOA accuracy at 100 yards, even with suppressed, subsonic loads. Our 416R alloy is the best barrel steel on the market when it comes to getting tight groups, and this upper’s M4 feed ramps, pistol gas system, 1:7 twist rate, and heavy profile ensure reliability and accuracy with any 300 Blackout load – subsonic, supersonic, suppressed or unsuppressed.
- 300 Blackout (7.5” Barrel & 7” Free Floating Quad Rail) AR 15 Complete Pistol Upper
This one’s easy, folks: If you’re looking for the most compact 300 Blackout upper possible, while retaining as much accuracy as possible, look no further. Our 7.5” 4150 Chromoly barrel assembly is one of the shortest on the market, making maneuverability and weight savings absolute. A free-floating rail helps ensure accuracy and provides convenient accessory mounting.
A heavy barrel profile helps ensure as much accuracy as possible as well, while a heat treatment process provides hardened rifling that brings those tight shot groups home and extends barrel life without the need for chrome lining – a process that adds cost and can kill accuracy. Although super-compact, this upper’s 1:7 twist rate and chrome-lined BCG help reliably cycle both supersonic and subsonic loads. At this price, our 7.5” barreled upper is also one of the most affordable AR 15 pistol uppers available – here, affordable doesn’t mean cheap.
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