Getting ready to get your feet wet with your first build? One way to make it easier on yourself is to build it with a completed lower receiver and then a complete AR build kit that has everything you need.
Another is with a lower parts kit and an upper, complete with all the upper parts you need. If you take this route, here are some things you need to know or questions to ask before embarking.
1. Does it come with a charging handle?
The charging handle is a part you’ll need to manually cycle the action. It is also needed to charge the weapon after loading a mag.
Without a charging handle, you will not be able to manually cycle the action and the rifle will not function as intended. Moreover, not all assembled uppers come with charging handles, though most do.
So check the specifications and make sure you’re aware of what you’re getting so you can save yourself trouble down the line.
2. Does it come with a forward assist or dust cover?
Unlike the charging handle, a rifle doesn’t really need a forward assist or dust cover to function properly, but they are useful parts to have, and not all uppers (complete ones included) have them.
The dust cover (also called an ejection port cover) is basically a part that keeps the ejection port protected from dust and dirt. It’s a simple, affordable part.
The forward assist is a little more important. Sometimes, for any of a variety of reasons, the bolt carrier group won’t return fully to battery, which means the rifle won’t fire when you pull the trigger.
It could be because of a fatigued buffer spring; it could be for other reasons, but either way, the forward assist lets you manually close the action all the way.
The rifle will fire without one, but it does help you close the action fully if you have any issues with cycling.
Again, make sure the complete upper you’re looking at has one.
3. Does it come with a bolt carrier group?
The bolt carrier group is the rifle’s heart, and unlike the charging handle, dust cover, and forward assist, the rifle will not function without one, as the bolt carrier group (or BCG, as it is often referred) contains the firing pin and spring, along with the extractor, ejector, and gas key.
Though many complete, assembled upper receivers come with a BCG, many do not.
This is not a cheap part, but it is just as well that you pick it on your own rather than that the upper comes with it, as there are many modern BCGs with advanced coatings that offer superior permanent dry lubricity and corrosion and wear resistance than standard mil-spec BCGs.
4. What is the barrel length?
All complete uppers come with a barrel (or they wouldn’t be complete) but barrel length matters here, and in no small part.
Barrel length will vastly impact performance, but here are the high level things you need to know:
- The longer the barrel, the more shot power there will be, so muzzle energy and muzzle velocity will be higher. Most shooters also feel that a longer barrel is more stable and more accurate, especially at greater ranges.
- The shorter the barrel, the lower the muzzle energy and velocity will be, but the rifle will be lighter and will handle more favorably, especially in close spaces. As a result, most shooters prefer shorter barrels (like 16” carbine-length barrels) for defensive applications.
5. Is the barrel threaded and if so does it come with a muzzle device?
Many assembled uppers come not only with threaded barrels, but with muzzle devices pre-installed.
Most of the time, the muzzle device will be a flash hider that helps prevent the muzzle flash from disorienting the shooter and obstructing the sight picture.
However, there are other muzzle devices, like muzzle brakes, that will drastically slash felt recoil, cutting muzzle flip and helping you keep your sights trained on target for faster, more accurate follow-up shots. So, if your upper is complete with a flash hider, consider swapping to a muzzle brake.
Also, if the barrel is threaded and does not come with a muzzle device, get a thread protector to protect the threads from damage.
6. What type of handguard does it have (and what other attachment points are there?)
Most assembled uppers will come with complete Pic rails (like quad rail uppers), KeyMod handguards or M-LOK rail systems. These have their own advantages and disadvantages so look into them before buying.
Also, the handguard may not limit mounting points; for instance, even an upper with an M-LOK rail system may still have a large section of Pic rail over the barrel, along with other mounting points, so shop carefully.
7. Do you need an FFL transfer to buy an upper, complete or not?
No, whether you buy a complete upper or just an upper parts kit, you do not need an FFL transfer to complete the transaction. This is because the ATF regulates the lower receiver as a firearm, and not the upper. An FFL transfer is required for a complete, functional lower receiver, but not for a receiver blank (AKA 80% lower). However, 80% lowers are not legal in many states and jurisdictions, so consult a firearms lawyer in your area before buying one.
8. What else will you need with an AR upper (not complete)
If you buy an upper complete with all of the parts mentioned here (including the BCG, charging handle, forward assist and dust cover) you will still need a complete lower receiver (not just a blank) along with a complete lower parts kit to complete the build.
Then, beyond that, you will likely just need a magazine. Assemble the rifle, which takes a few hours, and hit the range.
Start with a Complete Upper Receiver or AR Build Kit Here
Getting ready to start your next build? Get your complete assembled upper and parts here - we carry BCGs, barrels, gas systems, grips, stocks, magazines, and everything else you need to build your perfected, customized, personalized rifle.