Plenty of tinkers, firearms enthusiasts, competitive shooters, and hunters around the country build their own rifles from scratch every year. While the practice has been proscribed in some states and jurisdictions, in much of the country it remains legal for non-prohibited individuals to build their own rifles using an 80% lower or frame, a jig kit to complete the receiver blank, and a complete build or parts kit which contains the remainder of the upper and lower parts necessary to complete a functioning firearm.
On that note, if you take such a project up, you’re going to have to make a choice on whether you’d rather buy a complete, assembled upper, or complete your upper assembly with a stripped upper and the other necessary parts.
Stripped vs. Assembled Uppers (Complete Uppers): Know the Difference
The basic difference between a stripped upper and an assembled upper is in the parts contained in each.
Typically, a stripped upper receiver is just a milled piece of aluminum to which the rest of the upper parts can be attached. Stripped uppers are often one piece and come without ejection port doors or forward assists.
A stripped upper can be either a billet upper or what is known as a mil-spec upper. Mil-spec uppers are forged from 7075-T6 aluminum, meaning they are heated and “hammered” into shape before being milled out to take on their final form.
Billet receivers are made from a heated, extruded mass of aluminum that is then typically CNC machined to take on its final shape. Billet upper receivers can be made from either a multitude of materials, but commonly 6061-T6 and 7075-T6 aluminum are used.
By contrast to stripped uppers, assembled uppers contain all or most of the parts needed to complete a functioning firearm, meaning that in some cases an assembled upper can simply be attached to a matching lower receiver assembly to complete a functioning rifle.
What exactly comes with an assembled upper will vary, but typically assembled uppers contain a barrel, a handguard, a gas system, a BCG, and a charging handle. Some also come with a forward assist, an ejection port cover, and a muzzle device. However, some assembled uppers do not contain the latter five components, so make sure you read the description before purchasing one.
Buying an assembled upper will save you a lot of time and effort during the process, but if you’re looking to build a truly custom rifle, you may want to do so using a stripped upper and buying the other parts piecemeal. Here’s what you’ll need.
What You’ll Need to Complete a Stripped Upper
If you’re buying a bare-bones stripped upper, it’s likely not going to come with any of the following parts, which you will need to complete the build.
●BCG (Bolt Carrier Group)
The bolt carrier group, which is one of the most vital components of a rifle’s action, contains the firing pin, lugs, extractor and ejector, and the gas rings that enable cycling. You can choose a basic, affordable standard mil-spec BCG or opt for a modern version with a high-tech coating like black nitride or nickel-boron, either of which will exhibit excellent permanent dry lubricity.
●CH (Charging Handle)
Stripped uppers don’t come with charging handles and it’s pretty common for assembled uppers to lack them as well. However, you’ll need one to manually cycle your action and to clear jams. Mil-spec models are alright, but there are better models that are ambidextrous and port gas away from the user’s face - consider one of these and check out our recent blog on why you should upgrade your charging handle if you haven’t already.
●Barrel
Something you need to keep in mind if you haven’t ever built a rifle before: barrels are caliber specific so you need to keep that in mind when working on a home build project. For example, some barrels can fire both 5.56 NATO and .223, but will obviously be incompatible with .300 Blackout uppers containing .30 caliber barrels. Also, you choosing the barrel yourself instead of buying an assembled upper will give you the freedom to choose a longer or shorter barrel, affecting weight, balance, and handling.
●Handguard
An AR-15 complete upper receiver will come with a hand guard, while a stripped upper will not. However, you’ll need a handguard to protect your hands, protect the barrel, aid in heat dispersion, and offer you a place to mount accessories.
●Gas System (Gas Block and Gas Tube)
You will need a gas tube, which ports the gas from the barrel to the gas key of the bolt carrier group, as well as a gas block which fits your gas block journal. Make sure your parts are all compatible before buying them and give us a call before buying if you have any questions. Also, we recommend buying the slimmest compatible gas block to ensure that it fits under your handguard.
●A Muzzle Device
You don’t need to include a muzzle brake or a flash hider, but building an upper assembly from scratch gives you that freedom. A muzzle brake, for example, can significantly reduce felt recoil and keep muzzle jump to a minimum, enabling faster follow-up shots and less sight picture obstruction.
●Ejection Port Door (Dust Cover)
The ejection port door will allow the action to clear spent brass and rarely comes with stripped uppers. Double-check to see if an upper or upper assembly contains one and make sure you get one if it doesn’t.
●Forward Assist
The forward assist will help you “assist” the action in closing and locking the bolt carrier group if it fails to return fully forward and feed the next round. Some AR-15 upper receivers don’t come with it, so you’ll want to make sure you get one to complete your build.
Need Help Choosing a Stripped or Assembled Upper? Call Us
Questions about compatibility or what parts you’ll need to complete your build? We’re always here to help. If you’re undecided about tackling the project, for first-timers we suggest an assembled upper because they’re more of a plug-and-play solution, but if you want to go about it the hands-on way with a stripped upper, you can call us at 239-848-6757 or at Sales@MCSGearup.com.