For those that embark on a home build project in which an AR-style rifle is the goal, two receivers will be needed. An upper receiver, which accepts the barrel, BCG, and handguard, and a lower receiver, which attaches to the upper and which accepts the trigger group, mag, buffer system and stock.

With respect to the upper receiver, tinkerers have two choices. To build their own with a stripped upper receiver and sundry parts, or to get a pre-made, assembled upper that contains most of the parts need to complete the build.

Here’s what you need to know.
What Does an Assembled Upper Come with That a Stripped Upper Does Not?

Well, everything. Most assembled uppers come with basically everything you need to hitch up to a lower and create a functional home build.

Most assembled uppers contain:

● The upper receiver itself, machined or forged from aluminum

● A barrel

● A handguard

● The gas system (block and tube)

● The forward assist

● A charging handle

● An ejection port cover

● A muzzle device

Be aware that not all assembled upper kits contain a muzzle device, ejection port cover, or forward assist. Some may also not come with a charging handle so you’ll need to add that yourself.

Also, you may notice that “bolt carrier group” is conspicuously absent from that lineup, so make sure you get one for your home build.

You’ll also need a lower receiver (and if it’s a blank, you’ll need to finish machining out the slots for the trigger, fire control group, selector, and pins) as well as a lower parts kit to complete the build.

Flexibility and Customizability
Since the assembled upper comes with basically everything you need to complete the build, it doesn’t get the best marks for flexibility or customizability. Sure, you can swap out parts, but that defeats the purpose.

Conversely, while stripped uppers don’t come with any of the bells or whistles, they offer the best degree of flexibility and customization since you literally have to buy everything else piecemeal. A rifle made with a stripped upper is truly custom.

Cost is another consideration, but there is no easy answer here. Depending on how you go about it, it could be cheaper to do it either way.

Generally speaking, you could save a bit if you get an assembled upper and just take what comes with it. But if you start swapping parts out, you’ll lose those cost savings.

On the flipside, it’s possible to get parts cheap, but if you’re very selective about using only premium components, like Cerakoted handguards and nickel-boron coated BCGs, you’ll probably end up spending more on a build completed with a stripped AR-15 upper receiver.

So, it really depends.

This one’s no contest. Since an assembled upper comes with more or less everything you need to assemble the rifle, it’s going to be a lot more convenient (and save you time and effort) than creating one from a stripped upper.

Doing it the hard way, with a stripped upper, will take more time and effort on your part. But some people enjoy the process, so to each his own.

Do You Need to Use an FFL for an Assembled Upper?
You do not need an FFL transfer for either a stripped or an assembled upper. This can be confusing for some as you do need an FFL transfer of a completed frame or receiver.

But in the case of AR-style rifles, it is the lower that is considered a firearm and therefore that is the one that requires an FFL transfer. Upper assemblies (even complete uppers) do not.

For those interested in exploring their options, visit MCS Gearup online at, which carries assembled uppers, lower parts kits, build kits, and a wide range of other AR15 parts.

For more information about Buffer Tube and Caa Mck Please visit: MCS Gearup.