Building your own firearms is a satisfying, engaging hobby.
Assembling an AR-15 is not terribly difficult, but it does give you a deeper understanding of how the rifle works. I would recommend doing this at least once.
There are pistols you can build at home, too. Especially Polymer80s, which I prefer over OEM Glock pistols.
So you might see an AK parts kit for sale online and think to yourself, “AKs are known to be simple and reliable rifles. How hard can it be to build one?”
The answer is, “Pretty dang hard!”
Building an AK, even with a 100% receiver, is not like building an AR-15 or even finishing an 80% Glock frame. It takes machining skills and specialized tools.
But can it be done by the average Joe?
Can You Build an AK at Home?
The answer is, yes!
However, that’s not the real question.
The real question is whether doing so is worth your time and money. And building an AK, whether it’s a stamped AKM, AMD, or any other AK variant will take more than you expect of both.
The purpose of this article, therefore, is to lay out what it takes to build an AK so you can judge for yourself whether you want to build one at home.
AR-15s are assembled kind of like adult Legos. Polymer80s require some light drilling, filing, and fitting, but that’s still an order of magnitude below what it takes to build an AK.
In order to build an AK, you may have to do some or all of these tasks:
- Drill accurate “holes” across the top of a curved barrel
- Squash rivets
- Demill old rivets without egging holes
- Headspace the barrel
- Press components onto a barrel with hundreds of pounds of force
Basically, building a Kalashnikov-pattern rifle involves measuring, pressing, drilling, milling, and more. Often using metric tools you can’t find at your local hardware store. You’re not just assembling components here.
In fact, because there are so many AK variants, you’ll have to do a lot of problem-solving to put together even a pre-headspaced parts kit with all-matching parts.
But that’s not even the biggest hurdle for many people.
What Tools Do You Need to Build an AK?
If you want to build an AK, you’re going to need specialized tools.
Combloc AK variants are made on tooling and labor subsidized by the government. The cost of assembly wasn’t a big factor in the AK design as it is in many modern firearms, so actual Kalashnikov manufacturing is both tool and labor intensive.
This means that getting together the tools to assemble an AK can cost as much or more than the parts themselves. Many people find it cheaper to get a parts kit and send it off to a builder.
Building an AK with the right tools can include such tools as:
- Trunnion riveting jig
- Trigger guard riveting jig
- Trigger guard rivet drilling jig
- Riveting fixtures and bucking bars
- Barrel component alignment jig
- Metric drills, end mills, and reamers
- Trunnion press support
- Flat bending dies
And to properly use these, you’ll need:
- A good drill press or milling press
- A 12-ton or 20-ton hydraulic press
When even a trigger guard riveting jig can cost $65, you can see how these costs add up quick!
And don’t expect to save money by using a 100% receiver (which requires an FFL) and a headspaced kit. You’ll still need to press out the barrel to rivet the front trunnion to the receiver.
Kitchen Table Builds
If you’re willing to spend more time and less money then there are ways to use cunning instead of “The Right Tools”.
For example, you can crush the front trunnion rivets with a modified set of bolt cutters. A bearing puller can be used to press out the barrel. And a BFH (big flippin’ hammer) can be used (carefully!) to perform many of the tasks that “require” a hydraulic press.
You can also make your own jigs and fixtures.
If you want to put in the sweat equity, you can build an AK with a rotary tool, BFH, and scrap metal. But be prepared to sweat… a LOT.
There’s no shame in sending a parts kit off to a builder, as you’ll receive a gun you like and save time and some money!
Choosing a Receiver
Let’s look at the part of the gun considered to be the firearm in the eyes of the United States government:
You have four options when building an AK-pattern firearm:
- 100% receivers
- 80% receivers
- Receiver flats
- Sheet metal
A 100% receiver is legally considered a firearm, so you’ll need to have one shipped to your FFL if you buy online.
I’ve never seen an AK receiver for sale in a gun shop, but I’m sure it’s possible.
A 100% receiver is bent into shape, has all of the holes drilled and reamed, and has the rails welded.
You’ll need to add all of the other parts, which involves riveting two trunnions. You may also need to redrill the trunnion holes, fit the magazine well, trim the ejector, and do more fitting. So, 100% receivers still don’t have 100% of the effort finished.
100% milled receivers are easier because there are no trunnions to rivet. These components are part of the receiver.
An 80% receiver is bent into shape but doesn’t have most of the holes drilled.
Some 80% receivers come with the rails already welded, while others will require spot welding them in place.
You’ll need to drill out FCG holes, the safety selector holes, and the trunnion holes at least. This can involve using drilling jigs, using a template or layout guide and a center punch to mark the hole positions, or even very careful measurements.
You may or may not have to heat treat an 80% receiver. If you do then the best method for doing so at home is to use a MAPP torch to get the FCG holes and ejector red hot and quenching in water or oil. This hardens the holes but also makes them brittle, so you’ll need to apply not as much heat to temper the steel.
Pre-heat-treated 80% receivers don’t require this step but are harder to drill.
A receiver flat will have the holes pre-drilled, but likely not to the right size because they can make bending the flat difficult.
You’ll need flat bending dies to bend the flat into the right shape. Then drill and ream out any necessary holes. You’ll also need to weld in rails and heat treat the metal.
Truly hardcore AK builders can make their own receiver flat from a piece of sheet metal!
Most Kalashnikov rifle variants have 1mm receivers while some use a 1.5mm receiver. You’ll need to find or make a template and cut out every shape before bending it.
AK-pattern parts kits come in all sorts of configurations.
U.S. import law doesn’t allow for the importation of non-sporting firearms, which is why AK parts kits don’t come with a receiver. Barrels fall under certain regulations too, so most recent parts kits don’t even come with the original barrel.
Because there are so many AK variants, you’ll need to be absolutely sure that your parts kit, receiver, and barrel are all of the same type. An AMD barrel won’t fit an AKM parts kit without extensive modification.
Your parts kit will also determine the types of rivets you’ll need, too.
Building the AK
Once you have a receiver, a parts kit, and a barrel, as well as the necessary tools, you can start building your AK.
You will need to:
- Headspace the barrel to the front trunnion
- Populate the barrel
- Rivet the trunnions to the receiver
- Install the barrel
- Assemble the receiver parts
Headspacing is the single most important part of building an AK, so let’s start with this.
“Headspacing” means that you adjust the depth of the barrel inside the trunnion so that when the bolt closes on a cartridge the cartridge isn’t too tight in the chamber nor is it too loose.
Too little headspace (too tight in the chamber) will prevent the bolt from closing while too much headspace (the bolt closes with too big of a gap) can cause catastrophic failures.
Some people like to headspace the barrel to a loose front trunnion because it’s harder to move the barrel in and out when the trunnion is attached to the receiver.
On the other hand, you need to remove the barrel in order to rivet the trunnion to the receiver, so if you want to install the barrel only once then you need to headspace it after riveting.
The barrel is friction fit inside the trunnion, with an indexing pin across the top to hold the barrel more tightly in position. In order to headspace an AK barrel, you need Go and No Go gauges as well as a method to install and remove the barrel.
Use anti-seize on the barrel and the trunnion, too!
A barrel is properly headspaced when the bolt will close completely on a Go gauge and can’t close on a No Go gauge. You do this with the bolt stripped and out of the bolt carrier. A bolt is closed when it is stopped by the trunnion when rotated clockwise.
If the bolt closes on the No Go gauge then you have to press the barrel in further. If it doesn’t close on the Go gauge then you have to press it out slightly.
Once the barrel is headspaced then you need to drill for the barrel indexing pin, which is a 7mm pin that goes through the top of the barrel and the top hole in the trunnion. Use an end mill for the initial drilling because standard jobber drills will walk due to the barrel’s curvature.
You can use a 1/4″ 4 flute end mill, 6.5 mm drill, then 7 mm reamer. If you need to adjust existing headspace then drill it slightly larger and use an oversized barrel pin.
Make sure your barrel is perfectly aligned to the trunnion, too! You can use a rod set on the handguard retainer cutout to more easily see if the barrel is level. Or, you can populate the barrel first.
Installing the Barrel
The easiest way to install and remove the barrel is to press it with a hydraulic press. Make sure to avoid steel-to-steel contact by using a brass spacer and support the trunnion, not the receiver.
There are less expensive alternatives, too.
You can use a length of grade 8 all thread through the barrel to pull the barrel into the trunnion. Cover the threads inside the barrel with electrical tape to protect the barrel and put a brass nut on either side to protect the steel.
Thread on spacers (you can drill a hole through metal stock for this) to hold the trunnion on one end and a nut on the either end. Tighten both ends and you’ll pull the barrel into the trunnion!
You can use a bearing puller to push the barrel out of the trunnion.
Or you can use that BFH.
Hold the trunnion in a vise, protect the end of the barrel with brass or several sacrificial pennies, and gently tap the barrel into or out of the trunnion. Be careful, go slow, and consider the other methods instead!
Populating the Barrel
The rear sight block, gas block, and front sight block are all friction fitted and pinned to the barrel.
The optimum way of doing this is to use a hydraulic press. However, you can also use steel pipe to gently hammer them into position.
Then you’ll need to drill the pin holes for the 3 mm and 4 mm pins.
Don’t forget to add the handguard retainer after the rear sight block and before the gas block! If you forget this and don’t want to press off the gas block, you can find clamp-on handguard retainers.
You’ll likely need to drill the gas port hole. You can do this through the gas block with an extra-long drill. Use a smaller drill. Many AKs are over gassed. If you slowly enlarge the hole you’ll be able to hit that sweet spot without overgassing your rifle.
Make sure not to drill into the other side of the bore!
Also, before pinning your barrel components, make sure they are precisely vertical. You can find alignment jigs or make your own. Soviet spec allows for canted front sights so long as they can be sighted in, but you can do better than that!
If you press a component on and it’s not perfectly vertical then use a rubber mallet to rotate it into position before drilling and pinning.
Assembling the Receiver
After all of that, assembling the receiver is easy.
You need to rivet everything in place and insert the various components.
Insert the rivets so the head is flush with the receiver and crush them from the inside. You can buy riveting jigs or fabricate your own. Use a 5/16″ ball end mill to form the rivet head support divot in your bucking bar.
The FCG holes need to be reamed so they are exactly round if you don’t have a 100% receiver. A retaining plate can make installing the FCG axis pins easier.
You may have to adjust the trigger guard and magazine catch forward or backward in order to fit magazines. Use a steel magazine, preferably Combloc surplus, because US-made polymer magazines are sized differently. I’ve also had to open the rear of the magazine well. Go slow and prioritize using a file over using a Dremel.
The ejector often comes oversized; file it down a little at a time until the bolt barely clears it.
A helpful tip for smoother operation is to install the bolt carrier and lightly tap it downward with a mallet as you push it back and forth. This forms the rails to the bolt carrier.
Install everything including the dust cover and furniture. Congratulations! You built an AK!
Test Firing Your Rifle
But before you celebrate, it’s time to test your rifle.
Load some snap caps into a magazine and cycle them through the gun to make sure it feeds and ejects properly.
When you get to the range, don’t dump a magazine. Test fire a single round, preferably from behind a barrier using a cord tied to the trigger.
If that’s fine then check the headspace. Check headspace after the next five rounds, then after the next 10 rounds. If the headspacing doesn’t change, then you can celebrate!
A Note on Screw Builds
An old and affordable method for building AKs is to tap the trunnions for screws.
This takes less tooling, but please don’t do this to your gun.
Rivets fill in gaps when squashed and have strong shear strength. Screws don’t do this and have strong tensile strength. The connections between the trunnions and the receiver undergo shear stress.
Even if the screws don’t fall out or break under the stress, they’re likely to egg the holes in the receiver. AKs were designed to use rivets and riveting isn’t as hard as most people think.
Building an AK is a tough chore that takes up plenty of time and money.
It’s not a good choice for most firearm enthusiasts, but that’s okay.
However, there’s nothing quite like firing a gun you made yourself. And with an AK, you really made it yourself, you didn’t just assemble parts!
Whether that’s worth hundreds of dollars in additional expense is up to you.