Building an AK -- Part 1

With the successful resolution of my failure-to-extract issue, I've decided to discuss my thoughts (and lessons learned) on building an AK-74. This is not intended to be a primer (there are several sources of detailed information on builds available on the internet) but just a few pointers, ideas, and what I learned from the project.

Please note that I am not a gun smith, engineer, or machinist. These tips and thoughts are based on my own experience and are for educational use only. You should obtain proper instruction and training before attempting to use any tools or assembling a firearm. If you decide to use or apply these tips and thoughts, you do so at your own risk.

You Will Not Be Saving Any Money

First, and foremost, I want to emphasize that it is no longer economical to attempt to build an AK from a parts kits.Several years ago, you could get a de-milled AK kit (generally a Romanian AKM "G" kits) for around $70 dollars, that included the original barrel already seated in the front trunnion. Other types of kits, such as Polish underfolders, Egyptian made models, etc., were a little more, but included a barrel. The difficult part--seating the barrel and cutting the slots for the pins--was already done. This made it easier, and less expensive, for you--or a gunsmith if you sent the parts off for assembly--to build the rifle.

Then the Bureau of Alcohol, Tobacco, & Firearms (BATF) changed the import rules. The result is that kits are now much more expensive, and do not come with an original barrel (or have a demilled barrel, i.e., a barrel with a several large holes drilled into it rendering it useless and irreparable). When you add the expense of purchasing the barrel to the other 944r parts, it is nearly the same as buying a finished gun from someplace like Century Arms. When you add the costs of a gunsmith to assemble the parts (or the tools, if you are going to do the assembly yourself), you easily could be paying as much or more than you would for a really nice AK from K-VAR. My opinion is that if you are going to build an AK from a kit, it must be because of the joy or interest in the project, to test your skills or learn new skills, and not because you are trying to save a few bucks.

Parts

Obviously, the basic set of parts you will need will be a "parts kit"--generally this will include both the front and rear trunnions, gas tube, front and rear sight assembly, trigger group (the hammer, sear, and trigger unit--typically for select fire, unless from a Romanian "G" model), stock, pistol grip, top cover, recoil spring, bolt, bolt carrier and gas piston, and various springs and pins. Some sellers may include a U.S. made barrel as part of a packaged deal. If not, you will need to purchase a barrel separately.  Sometimes you can find an East Bloc barrel that is mil-spec with a chrome lined bore and barrel. Otherwise, you will need to get a U.S. barrel. To my knowledge, there are no U.S. made barrels that are chrome lined. Sources for barrels, parts kits, or individual parts, include Apex, Centerfire Systems, Cheaper-Than-Dirt, Copes Distributing, Sarco, and RTG Parts. There are plenty of other sources out there as well.

The next "part" is technically the firearm. This is the receiver. This is the part that is registered and bears the serial number. You have two options: (1) buy a fully manufactured receiver through a licensed firearms dealer, or (2) buy a receiver "flat" and manufacture your own receiver. The welding and bending of a "flat" is beyond my skills and ability, so I will not discuss it, but Tapco manufactures flats. There are several manufacturers of AK receivers, but I used one from Nodak Spud. If you have a gun dealer you work through, you can place an order with Nodak, then have the FFL holder fax his license to Nodak. The receiver will be shipped to the FFL holder, where you will complete the paper work for the transfer. Check about the transfer fee charged by the FFL before you order the receiver.

Next, you need to purchase parts to comply with BATF Regulation 944r. I won't go into it in detail, but essentially you need to have a certain number of key parts manufactured in the United States. Tapco has a good overview on their website (link here). Not all guns have the total number of parts in the list. My understanding is that you will need to get at least six (6) U.S. made parts for the AK, but I also recommend that you "overbuild" it with additional parts just to be safe.

The barrel and receiver are each one (1) part, so by this point, you already have two 922r parts.

You will also need to get a different trigger group since you can't use the select-fire/full auto trigger group that came with the kit. A new hammer, trigger and sear all count as a 922r part each, so a complete trigger group is three (3) additional parts. As you can see, just replacing the minimum parts you need already gives you 5 of the 6 required parts. I used an Arsenal Inc. made trigger group (available through Midway or K-VAR), but Tapco's trigger group has also received high marks.

A couple notes as to the trigger group, however. First, there are single-hook and double-hook triggers available. You can read up on the differences on the internet. However, the receiver has a small slot in front of hole for the trigger to accommodate the hook when the trigger is pulled. That means that a single-hook will need one-slot, but a double-hook will need two-slots. Not all receivers are built with two slots. So, unless you fancy yourself cutting a slot into the receiver, check your receiver before you order the trigger group. I used a single-hook so I didn't have to worry about the issue.

Second, you may be tempted to pitch the full-auto trigger group that came with your kit. Don't. There is a small spring that fits between the trigger and the sear that you will need. Take the trigger/sear/rate reducer apart after wrapping in a cloth. The spring will jump out, so the cloth will catch it. (Trust me, the spring is very small and hard to find). After you have removed the spring, then you can throw the old trigger parts away.

The other parts to replace with 922r parts depends on your taste and what you want. If you want to use a non-U.S. stock and/or pistol grip, you may have to get creative. However, the stock is the easiest part to replace. The fore-stock, pistol grip, and butt stock are each one part, so replacing all three would give you a total (with the receiver, barrel, and trigger group) of 8 parts, which is well in excess of what is required under 922r.

Another part that is easily replaced is the flash-hider/muzzle compensator. The gas piston can be replaced, and some people will use U.S. made magazines (three parts--body, floor plate, and follower) or use a U.S. made floor plate or follower on a foreign made magazine body.

I opted for a U.S. made stock set. I chose the set available through K-VAR because it was the only U.S. made synthetic stock set with a heat shield in the forestock. (Note: K-VAR also sells foreign made stock sets, so double-check what you are ordering).

Another part you may consider, although it is not necessary, is a retaining plate to hold the trigger group pin in place. Tapco builds one (link here).  Here is a different style (a "shepherd's crook") at Brownells. (Link here). You can also modify one of the springs to clip into place. Strangely enough, Tapco has modified spring clips that you can also get (link here). I've had experience with the shepherd's crook style, but made my own spring clip out of a spring. (Some instructions here). It will save you a lot of time and expletives if you use a retaining plate.

Once you have the parts you need, you can ship it off to a gunsmith to assemble. Otherwise, you are ready to start down the hard road of becoming a DIY gunsmith.

Rivets Versus Screws Versus Welding

For the DIY gunsmith, the next issue is deciding the method to assemble the component parts--specifically, attaching the receiver to the front and rear trunnions, as well as attaching the trigger guard and magazine release assembly to the receiver. 

The great debate (and it can be contentious) is using rivets versus using screws. You will also find a few people discussing welding. As I noted above, I don't do welding, so I won't discuss that option any further. The people arguing for rivets make two basic arguments: rivets are what the original design called for; and screws are too weak and loose to hold the gun together. Well, there is no doubt about the use of rivets by the Soviets, but in my research, I never came across anyone that actually experienced a failure due to a screw breaking. If there were any problems with screws, it was with the screws backing out, which problem was solved with a bit of Lock-Tite.

I decided on a screw build. My reasoning was that I thought it would be easier than attempting to build with rivets, it would be cheaper, and if I had issues, I could dissemble the parts if I needed. One of the issues that particularly concerned me with a rivet build was the actual process of squeezing the rivets. The professionals that built lots of AKs had special jigs for use with a hydraulic  press, which cost several hundreds of dollars. Other people modified bolt cutters to use to squeeze the rivets.

However, whichever way you go, you will need to get either rivets or screws. Various companies make rivets for assembling an AK. Screw kits were harder to track down. Although Tapco makes a set of screws, you can't purchase directly from Tapco, and there were only a couple of parts dealers that carried the screw sets. Of course, you can also go to your local hardware store for the screws, which is what I did, selecting stainless steel screws. If you do go the screw build route, I would recommend getting two sets of the screws just in case.

Tools

I'm going to assume that anyone getting into a project like this has basic hand tools like a ball-peen hammer, punches, various types of pliers, a vice-grip, etc. I also assume that you have some lubricant for easing the barrel and various pins into place. My focus will be on some of the non-standard tools.

Since you will be seating (pushing) the barrel into the front trunnion, you will want a hydraulic shop press. (Here, for example). This will come in handy for pressing the barrel pin. I suppose that you could use a heavier hammer to hammer the barrel in place, but it is a whole lot easier to have the press.

You will have to cut slots in the barrel for various pins, and you may need to open up some of the holes in the receiver for the screws. For this, you will need a Dremel or similar rotary tool. For the actual cutting, you will want to get 1/8 inch tungsten carbide cutter (Craftsman parts no. 953071) and 5/16 inch diamond point cutter/engraver (Craftsman parts no. 953161). The latter actually comes with two cutters/engravers--you will only need the pointed one; the one with the bulb tip is unnecessary for this project.

Of course, if you decide on a screw build, you will need the appropriate sized and thread tap and a tap wrench. 

I discovered that the hole in the front trunnion for the barrel was actually too small. Ideally, you would use a flapper wheel to open it up but keeping it uniform in diameter. However, I couldn't find one that was the right size. I eventually decided on a 1-1/8 inch brake cylinder hone. (See, for example). It was still too big, but by removing one of the stones, I was able to fit it in and broaden the hole. If you have to do this, be very careful--you want the hole to be big enough that you can fit the chamber end of the barrel into the front trunnion, but tight enough that you will have to use the press to seat the barrel. In my case, just a few seconds of use (probably enough to grind off 1/1000 inch of material) was enough.

In my next post on this topic, I will discuss tips and pointers as to the actual assembly process.