Taming the Beast, Silencing an AK-47

Using Your Mary-Sue Suppressor on an AK Variant

Warning!
When handling firearms, always observe safety rules and the precautions set forth in the firearm’s owner’s guide. Be certain that your firearm is unloaded and made safe before proceeding with this DIY.

Want to silence an AK? You have an uphill battle. Back in Issue 26, we covered a pair of dedicated AK silencers — one from Gemtech and another from Dead Air. Since that time, a handful of other purpose-built Kalashnikov suppressors have been released, but what if you don’t want to buy a silencer specifically for an AK? That’s what this article is for.

Chances are, if someone only owns one silencer, it’s either for 22LR or for 7.62N — this piece is for those who fall into the latter category. A 7.62N silencer as a “do all” is a very common first NFA purchase. The rationale behind a 7.62N can is pretty simple: companies typically advertise them as being good for 5.56 and other smaller calibers as well.

But if you want to use your normal 7.62N silencer, undoubtedly not designed for AKs, there’s some work you have to do to overcome the issues. Threads are often not concentric to the bore — blame Soviet precision. Rarely is an AK thread pattern readily available in your standard fare silencer, and there’s no shoulder to speak of for a silencer to seat against. AKs are already so overgassed; adding backpressure from a silencer just makes it a heavily recoiling mess.

And yet, it can still be done. We’ll show you a variety of ways to overcome these issues, all while using your normal 7.62N silencer. These methods can each be used piecemeal, or you can combine them. Before heading to your workbench, be forewarned that not all suppressor companies will honor their warranties if used on an AK, for all of the reasons we’ve already outlined.

ADAPTERS
First and foremost, we have to address the thread patterns on an AK. By far the most commonly seen thread pattern on a 7.62×39 AK is 14x1LH, though 24mm x 1.5mm takes second place, especially with 5.45 AKs. Other threading exists, like 22mm (for Romanian 5.45/5.56 guns) and 26mm specifically for some Yugoslavian AKs.

The more parts you stack, the more you increase your odds of a baffle strike.

Regardless, your standard 7.62N silencer is unlikely to come in one of these thread patterns. For best results, you should send your rifle in to be threaded properly in 5/8×34 — but not only can this be costly, it’s also often impossible. So you’re left with thread adapters.

Always ensure your bore rod fits perfectly on the bolt face.

But you can’t just buy the first $15 thread adapter you find on Amazon. One major issue is that AKs don’t have a solid shoulder to butt up against, instead utilizing a front sight block right at the end of the threads. Using adapters, in general and on AKs in particular, is a bad idea — you’re stacking tolerances that you don’t want to and exponentially increase your chance of a baffle strike.

If you have to use a thread adapter or a custom muzzle device for your patterned AK, use one that indexes on the muzzle itself and not on the front sight. We recommend the Griffin Armament thread adapter for general purposes, and not just some random one you found online cheap.

Left side: Gap (good); right side: No gap (bad).

Take care to note that any specialized quick disconnect adapter threaded for an AK also should index on the muzzle, not the front sight. If your thread adapter or muzzle device threads completely on, indexing on the front sight instead of the muzzle, it’s a poor choice for use with a suppressor. If you just want a muzzle brake? Go with God. The main concern with suppressors is that any angular deviation from the bore is exponentially exacerbated the longer the device that you attach. A stubby 1-inch brake may give you no issue, but the same can’t be said of a 6- or 10-inch silencer.

Cost: $60 to $70

RODS
Even if your chosen silencer has a thread pattern that works directly with your AK, you absolutely need to check alignment before firing to ensure you avoid a baffle strike and the shrapnel that can come along with it. With an AR-15 or similar, it’s a fairly straightforward process to pull an upper and eyeball it, but the same can’t be done with an AK. Even if you strip everything down, the rear trunnion will get in the way of a completely straight view down the muzzle. So what can you do? Rod it.

Opinions vary on what alignment rod to use, with Geissele generally considered the best and CNC Warrior rods as a second. Some use precision drill rods from McMaster-Carr for the same purpose, though the tolerances aren’t as precise as Geissele’s offerings.

After mounting the silencer, insert the alignment rod into the end of the suppressor and allow it to fall to the bolt face of the rifle. If any point of the rod makes contact with the silencer — consider it a no-go and do not shoot the AK with the silencer attached.

If any part of the alignment rod touches any part of the silencer — no-go.

If you’re using either a 5.45 or 5.56 AK with a 7.62N silencer, you have a bit more wiggle room for alignment, but you still shouldn’t pull the trigger on a rifle that fails an alignment test. AK-specific silencers, such as the Dead Air Wolverine PBS-1, use baffles with apertures that get continually larger further down the suppressor to help mitigate misalignment — but even still, don’t shoot a gun that doesn’t pass a rudimentary rod test.

Cost: $19 to $75

SPRINGING IT
As mentioned, AKs are gas hogs. Part of the mythical reliability of an AK-series rifle stems from the fact that they tap so much gas from the bore, allowing the bolt carrier group to fully cycle even when extremely fouled. Attaching a silencer to the end exacerbates this, with the backpressure the silencer creates pushing gas not only through the piston system, but also back through the barrel itself.

This leads to greater recoil and increased parts wear. No, regardless of what you’ve read on a gun forum someplace, the AK isn’t infallible and can and will break.

Adding heavier springs doesn’t solve the problem of excessive gas, but it does cut down on the symptoms. The addition of more robust springs will not only reduce recoil and muzzle rise, but will increase internal parts longevity. While there are several options, we’ve found the Snakehound Machine (SHM) spring kits to be fantastic for this purpose.

Not only do you receive a much stronger recoil spring in the pack, but also a hammer and extractor spring (the latter must be cut to fit). With most AKs, the SHM kits will work suppressed or unsuppressed, because the AK-series rifles have such a large operational window.

Swapping recoil springs on an AK may seem daunting at first glance, but it’s actually a fairly easy process. To replace your recoil spring:

1. Remove the recoil spring assembly.
2. Pull back on the spring and use a pair of vise grips to hold the recoil spring to the rear.
3. Spread the two spring bars to remove the end piece of the recoil spring assembly.
4. Remove the current recoil spring (Watch out! It can fly off).
5. Install the new SHM recoil spring and hold it to the rear with vise grips.
6. Spread spring bars apart to reinstall end piece.
7. Remove vise grips and reinstall the parts.

A pair of vise grips makes swapping in Snakehound springs a snap. Without them, you’re liable to lose an eye.

Even if you choose another method for suppressing an AK, the SHM spring upgrade should be used in conjunction with it.

Cost: $25

BUFFERS AND GAS BUSTERS
The increased gas from the addition of a silencer means your bolt speed will be higher than usual. While a standard buffer setup will protect your rear trunnion from undue wear from bolt cycling, it also reduces some of the leaded gas rolling into your face. But you can take it a step further.

A common AR-15 mod is making a “DIY Gas Buster” charging handle utilizing RTV silicone, and the same can be done with an AK. For this mod, all you need is a cheap AK buffer, some cooking spray, and black RTV silicone (commonly available at any auto parts store).

Black RTV Silicone being squished on as a seal against gas may look ugly — but it’s effective. Not that the insides of AKs are pretty anyway …

While red RTV silicone is most commonly used on an AR, the black is more resistant to oil, so we utilize it for our purposes.

1. Field strip AK and degrease.
2. Install buffer on recoil spring assembly, install back into BCG.
3. Spray rear trunnion and inside of top cover with cooking spray to act as a release agent.
4. Gob the black RTV silicone onto the buffer and in/around rear trunnion.
5. Replace top cover.
6. Allow silicone to cure for 24 to
48 hours.
7. After curing, disassemble AK, remove excess cooking oil.
Ugly? Absolutely. Functional? You betcha. Gas to the face is significantly reduced.

Cost: $18

GAS PISTONS
Every fix and solution up to this point only addresses the symptoms and not the root causes. But not this one. The KNS adjustable gas piston allows gas to vent from the piston itself, slowing the movement of the BCG. Less parts wear and reduced recoil — what’s not to love? Well, a couple of things:

At the time of this writing, 19 different pistons are available covering the vast majority of AK/AKM variants. You’ll need to choose the one that corresponds to your rifle.

In order to install the KNS gas piston, the original piston has to be removed. For many guns, this just involves a punch and a hand drill. But if you’re unlucky enough to have a piston that’s welded in place, like many CAI imported guns, installation is far more daunting. There’s no guarantee that you won’t destroy your bolt carrier in the process of removing a welded piston, and many don’t consider it a worthwhile venture.

While drilling and tapping the gas block is the most extreme option, it can be performed with simple tools.

If you have a standard pinned carrier, removal of the OEM piston and installation of the KNS is fairly easy. All you need is a vise, hand drill, 1/8-inch punch, and 1/8-inch drill bit. OK, maybe a Dremel too.

1. Strip the BCG and put in a vise.
2. Locate the rivet head; sometimes you’ll have to remove some finish to find it.
3. Partially drill the rivet out, and use the punch to completely remove.
4. Rotate out the OEM piston.
5. Install the KNS piston and secure with the included roll pin.

After installation, the piston has to be tuned. There are over 100 settings, so it may take you a bit of time to find your desired sweet spot. Also, bear in mind that the piston will have to be adjusted when taking the silencer on or off for optimal performance. Note that since the gas is vented internally, though carrier speeds are reduced, you’ll still get the additional gas in your face.

Cost: $149 to $165

CUSTOM GAS BLOCKS
This option is for those more daring-minded, as it involves permanent modification to your rifle. Unlike the KNS gas piston, this modification vents excess gas to the atmosphere, virtually eliminating any gas to the face. But in addition to permanent modification and tuning, you’ll now have some small parts to keep track of.

1. Using a #21 drill bit (5/32 is the closest fractional size), drill a hole in the gas block forward of the end of the gas piston.
2. Thread the hole to 10/32, utilizing a quality tap and handle.
3. Obtain several vented cup-point cap screws — McMaster-Carr sells a 10-pack for $5.16 (PN 7573841421).

Now it’s tuning time. Head to the range with the rifle and silencer of your choice, along with a set of numbered drill bits and a cordless drill. Since an AK is already so vastly overgassed, there’s a decent chance it’ll run unsuppressed with just the standard vented cap screw. If it doesn’t, obtain an unvented cap screw from your local hardware store for unsuppressed use.

Install your suppressor and slowly open the hole in the vented cap screw until it reliably cycles at the speed you desire. While we’d normally advocate for a drill press, it’s not practical for most to run to the range with them. A field expedient method is to use a pair of vise grips to secure the vented cap screw while drilling.

If you make the hole too large? Well, maybe that’s why McMaster-Carr sells it in a 10-pack.

For our particular rifle/silencer combo we have one cap screw for suppressed, and another for unsuppressed. The extra screw, along with a hex key, is stored in a small baggy that conveniently fits into the AK cleaning kit.

Cost: $10

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