There are numerous reasons to build with a stripped AR15 upper as compared to a complete one (see below) the chief of which is the flexibility to customize the rifle, piecemeal, during the build.
With that in mind, here are the 4 best parts to customize for performance along the way.
The Barrel
The barrel is one of the most important AR15 upper parts of all and for obvious reasons. More than another other part, the barrel will impact power, handling, accuracy, and performance.
For instance, barrel length is the most obvious trait you can customize. A 16” barrel will be lighter and shorter than a 20” barrel, and will result in a lighter, more compact overall rifle that will likely handle better in close-quarters.
Barrel length can also influence accuracy. While some consider longer barrels more stable, they often exhibit more barrel whip that can complicate accuracy. With that said, the longer sight radius of a longer barrel is more forgiving.
Barrel length is also directly tied to power, as a longer barrel will trap expanding gasses for longer, giving the bullet more time to accelerate before it leaves the bore.
So, as you can see, there are numerous factors that have to be considered here.
The Muzzle Device
Many AR15 upper kits, or just barrels, come with muzzle devices attached (assuming the barrel is threaded, and they almost always are). That muzzle device is almost always a flash hider.
Well, this is another AR15 upper part that you almost certainly will want to reevaluate. Flash hiders obstruct the muzzle flash, helping to keep your sight picture clear, but that’s about all they do.
A compensator is a more practical muzzle device, as a compensator can significantly cut back on felt recoil and muzzle flip. In fact, a good comp can diminish felt recoil by as much as 50% without affecting shot power, which in the case of most AR builds will virtually eliminate felt recoil altogether.
Another option is a suppressor, which will not only cut felt recoil, it will lower the muzzle pop and report of the rifle, obstruct the muzzle flash, and increase power by a bit.
Either way, both suppressors and compensators offer much better, more practical performance than flash hiders.
The Bolt Carrier Group
Most AR15 uppers that come with a bolt carrier group (BCG) will come with a mil-spec model, which is phosphate-coated. Mil-spec BCGs are alright. They’re non-reflective and relatively corrosion-resistant but they also need a lot of liquid lubricant (comparatively, at least).
There are many different types of bolt carrier groups out there that have advanced modern coatings that perform far better than phosphate. Some of these are DLC (diamond-like carbon), nickel boron, black nitride, and titanium nitride, which has an extremely attractive gold tone finish.
In all cases, these bolt carrier group coatings, despite the fact that they are much more expensive than standard mil-spec BCG coatings, offer much higher permanent dry lubricity, which diminishes wear, increases cycling fluidity, and needs less liquid lubrication.
The AR15 Charging Handle
You won’t gain a huge advantage in performance or ergonomics by swapping your AR15 upper’s charging handle, but there are some charging handles out there with a larger form factor and which are ambidextrous, making them easier to locate and manipulate intuitively, in the dark, or in the cold with heavy gloves on. There are also AR15 charging handles that help redirect gases away from the operator’s face, which some also prefer.
The Gas System, Specifically the Gas Block
Lastly, one more AR15 upper part you might want to upgrade as you go through the motions of selecting parts and assembling the build is the gas system, specifically the gas block.
Two potential upgrades are low profile and adjustable gas blocks. In the case of a low profile gas block, these are preferable with use with low-profile handguards, as they fit underneath handguards without obstructing anything.
An adjustable gas block is perhaps even better, as they can be adjusted - as the name suggests - to fine tune action cycling and performance. The ability to adjust the gas block can enable the action to run more fluidly, decrease wear on the gas key, and streamline extraction and ejection.
Why Build with a Stripped AR15 Upper?
Building with a stripped AR15 upper as compared to a complete upper gives you a lot of flexibility in terms of customization. Also, depending on how you build, you might be able to save money, and on top of that, it will teach you a lot about rifle assembly and make you a more informed owner.
For more information, shop our collection of AR15 uppers and get in touch with us at Sales@MCSGearup.com if you have any questions.