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AR-15 Upper Assembly Basics

AR-15 Upper Assembly Basics

Posted by Black Rifle Depot on Apr 13th 2019

For new builders, the amount of choices available when it comes to designing an AR-15 are almost endless. To help make your decision easier, Black Rifle Depot is always here to assist. We have a wide variety of AR-15 upper assemblies to choose from, but for the beginner, we’ve selected a few that we think make the most sense, based on your specific needs.

AR-15 Upper Assembly - Deciding the What and Why

The first step in selecting an AR-15 upper assembly is deciding what exactly the purpose of your new AR-15 build is going to be. Are you looking for a range toy? Are you looking at something that you need to be compact and portable?

Are you looking for a practical, general purpose AR-15 that can also pull duty as a self-defense firearm, or are you perhaps looking at shooting targets at distance? Deciding this up front before you put together your AR-15 is going to be a tremendous help.

Keep in mind, building an AR-15 has never been easier or cheaper. It could be that you even decide to build two (or more)…each for a different use. That said, let’s take a brief look at just a few of the AR-15 upper assemblies that Black Rifle Depot offers. We’ll take a brief look at short, medium, and longer range AR-15 upper assemblies.

Short-Barreled Rifles or Pistol Builds

Depending on the laws in your state and your willingness to do extra paperwork, a Short Barreled Rifle (SBR) can make for a very handy package. Obviously, NFA rules do apply. You’ll most certainly need to research that. That said, instead of an SBR, many builders today are opting to build AR pistols.

If you have decided to go that AR pistol route, then Black Rifle Depot offers a few different short 5.56 AR-15 upper assemblies that are both affordable and reliable.

7.5" 5.56 NATO Pistol Upper Assembly

Our shortest option is a 7.5" 5.56 NATO Pistol Upper Assembly that features a 4150CMV steel barrel, a 7" M-LOK handguard an A2 flash hider, 7075-T6 Forged Upper Receiver, a forward assist and dust cover, and our lifetime warranty from Black Rifle Depot.

This 7.5” length pistol upper assembly makes for a very fun but boisterous range gun. We run our little AR pistol with a black nitride bolt carrier group and have put just over three thousand rounds thru our personal T&E gun without a hiccup. it’s a tiny package that runs and runs, and is about as much fun as you can have with a small AR pistol.

I would stress that, in our experience, this is an upper assembly I’d go with for fun above practicality. I’d also warn you that 5.56 out of a 7.5” upper assembly is quite loud. Loud may even be an understatement. I’m fairly certain, that given a choice, I’d NOT want my home defense AR sporting a 7.5” barrel.

That said, the next step up is a lot more practical in that regard.

10.5” 5.56 NATO Pistol Upper Assembly

If you’re still liking the idea of an AR pistol build but don’t like the idea of a super short 7.5” barrel, an obvious solution is the 10.5” 5.56 NATO Pistol Upper Assembly.

This is a length where, ballistically, with the right ammo, it could make for a very mean little defensive AR pistol. You’re only adding 3” to the gun, but that length addition, in our opinion, bumps it out of ‘range toy’ category and into an area where you could seriously consider this as a trunk or behind-the-nightstand pistol, depending on your needs.

Our 10.5” 5.56 NATO Pistol Upper Assembly has the same features as the 7.5" 5.56 NATO Pistol Upper Assembly, and paired with one of our bolts, you have a very handy, reliable and practical AR-15 pistol.

One caveat: Even at 10.5”, these upper assemblies are still loud. As long as you know what to expect going in…carry on.

16” AR-15 Upper Assemblies 

For many first time builders, the 16” AR-15 Upper Assemblies are the sweet spot. I’d go so far as to say, for most people, in most circumstances, a 16" upper assembly is the ideal all-around choice.

With this size you get the most out of the rifle from a ballistic standpoint. The gun will be softer shooting, the concussive blast present in the shorter barrels is not a huge factor, and it’s an overall very practical length for a wide variety of uses.

If pressed on what length to go with, we always recommend the 16” AR-15 upper assemblies over any other length we sell at Black Rifle Depot.

16" 5.56 NATO Upper Assembly

Weighing just 3 pounds and 12.5 oz., the 16" 5.56 NATO Upper Assembly is a true workhorse and one of our most popular AR-15 upper assemblies.

It features a quality 5.56 Ballistic Advantage Modern Series barrel, a 15" Slim M-LOK Hand Guard .750 Steel Gas Block (QpQ Nitride), 7075-T6 Forged Upper Receiver, A2 Flash Hider (QpQ Nitride), and Standard Mil Spec Charging Handle.

Pair this upper assembly with a bolt from Black Rifle Depot and you’ve got a reliable and affordable upper assembly that is a perfect introduction to the AR-15.

16" 5.56 NATO Super Slim Upper Assembly

For a slightly slimmer and lighter option, please know that we do offer the 16” 16" 5.56 NATO Super Slim Upper Assembly. It features a 5.56 M4 Profile 1:7 Twist Barrel (QpQ Nitride), Carbine Length Gas System, our 15" Ultra Light M-LOK Hand Guard, .750 Steel Gas Block (QpQ Nitride), 7075-T6 Forged Upper Receiver, Elite Muzzle Brake (QpQ Nitride).

16" Stag 15 VRST S3 5.56 Upper Assembly

For a slight step up, be sure to take a look at the Stag 16" Stag 15 VRST S3 5.56 Upper Assembly. The VRST S3 Uppers feature Stag's high quality and long-lasting durability standards, outfitted with Diamondhead's lightweight, free float 13.5" VRST Series 3 M-LOK Handguard.

The Stag 15 VRST S3 Upper features a 5.56x45mm NATO chamber 16" 1/7 chrome lined barrel with a 13.5" free float M-LOK handguard and A2 birdcage flash hider.

Also included with this upper assembly is a Mil Spec Bolt Carrier And charging Handle…so you have everything you need in one convenient and affordable package.

APOC Armory 16" Titan .223 Wylde Cold Hammer Forged Upper Assembly

Another affordable and reliable option is the APOC Armory 16" Titan .223 Wylde Cold Hammer Forged Upper Assembly. The APOC Armory Titan upper assembly comes standard with our black nitride barrel. These uppers are assembled on a forged 7075-T6 anodized receiver with t-marks.

For this particular upper assembly, we went with an ultra light weight 15" free float M-LOK hand guard. The gas block as well as the muzzle device are black nitride treated to match with the barrel. Also, included, you have your choice of black nitride or premium nickel boron BCG with extended latch charging handle.

These uppers have a 1" MOA Guarantee as well as unconditional lifetime warranty on all parts and labor.

Finally, the APOC Armory 16” also has a mid-length gas system worth noting. It’s the system I enjoy on my personal 16” rifles, as I feel it’s smoother shooting and perhaps aids in reliability.

Dirty Bird 16" Govt Mid 556 M-LOK Complete Upper

This Dirty Bird Industries Complete Upper features a Black Nitride 16" Sub-MOA Government Profile barrel chambered in 5.56 with a 1:7 twist. Built on a top-tier t-marked Forged Upper Receiver and finished with Dirty Bird's 15" SMRS M-LOK Handguard available in several color options.

No corners are cut when manufacturing these complete uppers. All barrels are dimpled and cold blued, use a black nitride 4140 steel gas block and a stainless steel gas tube. The gas block set screws feature knurled cone tops and are installed using blue locktite ensuring that no amount of firing will cause the set screws to come loose but they will still able to be removed for servicing if needed.

This upper assembly also has a mid-length gas system, which we love.

As far as reliability, this is an upper assembly that I trust to absolutely function when I need it to. It's an absolutely tremendous upper. One caveat...it does not come with a BCG or a charging handle.

18" .223 Wylde Spiral Fluted Upper AssemblyFinally, If you’re looking for a bit longer barrel, we have you covered with the 18" .223 Wylde Spiral Fluted Upper Assembly. It features an 18" .223 Wylde Spiral Fluted 1:8 twist, Mid Length Gas System, 16.5" Keymod Hand Guard, Steel Black Nitride .750 Low Profile Gas Block, 7075-T6 Forged Upper Receiver With FA/DC, and a Competition Black Nitride Muzzle Brake.

While we almost always prefer a 16”, some shooters feel that the 18” gives you slightly less recoil impulse, and you do get a slight bump in velocity. Before deciding on an 18”, I’d most certainly do a bit more research and find out of you really need it. We think for the most, the 16” is usually the way to go.

In conclusion, no matter which AR-15 upper assembly you choose, any of the above will provide you with a strong and reliable starting point for your new AR build. Regardless of what you choose, just know that we have you covered at Black Rifle Depot. We also understand that these sorts of topics can be confusing for a beginner. We hope this blog helps, but if not, please know we’re here to help and walk you through your purchase.