The SKS (Samozaryadnyj Karabin Simonova) or Simonov self-loading carbine is a Soviet semi-automatic assault rifle designed in 1943 by Sergei Gavrilovich Simonov. It was introduced immediately after the end of the Second World War and was entirely up to the military concept of that time combining features from 19th-century Mosin-Nagant, semi-automatic AVS-36 rifle, and the PTRS-41 anti-tank rifle.
In other words, the newly developed semiautomatic battle rifle featured a permanently attached bayonet, intermediate M/43 7.62x39mm cartridge, and scaled-down, anti-tank rifle action also designated by Simonov.
While the SKS's integrated sword bayonet made many generations of conscripts justifiably nervous about their fingers and hands, the rifle itself was capable of remarkable shooting accuracy followed by as moderate and soft a recoil as you can get, launching 123-grain bullets at 2,300 fps.
Comparison Chart of the Best SKS Gas Tubes
NcStar SKS Gas Tube Scope Mount w/Side Rails
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Tapco - SKS Gas Tube W/handguard
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Tapco SKS Gas Tube W/Handguard
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Tapco SKS Yugo Gas Tube W/Handguard
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What is a Gas Tube and What is it Used For?
By definition, a gas tube or gas cylinder is part of gas-operated firearms, which serves to carry gas from the gas block to the gun receiver, where gas powers the bolt carrier group and cycles the next cartridge from the magazine.
The SKS is a gas-operated rifle with a locking system that uses a tilting-bolt operated by a short-stroke gas piston. Unlike the AR's “direct impingement” gas system, the SKS gas tube sits under the handguard, housing the gas piston, which moves the gas piston rod, and finally activates a spring-loaded bolt carrier.
The gas tube in this Simonov design connects directly up to the gas block on the barrel and is actually the mechanism which carries the gas from the spent cartridge to the piston.
How to Choose a Gas Tube For Your SKS
As you know, the SKS is not a modern platform. More precisely, it is a 1930's design, but you can enhance its capabilities utilizing few accessories.
Even in the 21st century, the SKS is a great survivalist carbine, but it does need a few upgrades. Indeed, one of the most recommended modifications is altering the gas tube together with the handguard.
Although the SKS battle rifle had a relatively short service history, you need to be cautious about its different patterns with some short-barreled and grenade-launching variants. Though there are relatively few versions of the SKS, you should be aware of the different gas cylinders from various makes and patterns.
While the standard SKS cylinder measures 9-19/32" (244mm) overall, the cylinder of the SKS 'M' Sporter at 8-7/8" (225mm) is shorter than a regular paratrooper gas tube. There is also the Yugo 59/66 gas cylinder, which is 9-11/16" (246mm) long and Albanian at 9-9/16 inches (243mm) in length. Additionally, the Albanian SKS might be incompatible with the most of replacement gas tubes due to its extended handguards which completely cover the gas tube.
The next question is what the replacement gas cylinder is good for. As we primarily talk about military surplus guns with likely worn or damaged gas tubes, replacement gas cylinders with a new bore are almost obligatory parts.
The second reason is the ability to shoot accurately, since most of the replacement gas tubes come with a Picatinny rail for mounting “scout” style optics and red dot sights.
Unlike classic receiver-cover scope mounts, this gas tube rail will preserve the rifle’s stripper-clip method of loading and will not hinder field stripping and cleaning.
As an added benefit, some Picatinny rail features a groove, so iron sights are still usable when a scope is mounted.
Once we've determined the proper gas tube length and the given advantages, our next step is to decide what type of cylinder we want to mount. Since the aftermarket offering is not as overwhelming as for AR-15 or AK-47 parts, our job is much more simple and straightforward.
Review of the Best SKS Gas Tubes
Time to take a closer look at some of our top picks. Let's see what makes each model stand out:
NcStar SKS Gas Tube Scope Mount W/Side Rails
If you have been looking for a "scout" style scope base but are skeptical about getting an after-market plastic part for such an old gun as an SKS, you can choose a heavy-duty gas tube of aluminum and steel construction from California-based manufacturer, NcStar.
The NcStar SKS steel gas tube comes with an aluminum Picatinny rail scope mount which also has dual side rail sections. These two Picatinny side rails are removable and can be mounted into any of the six ventilation holes, adding some flexibility for mounting lasers, flashlights, or other accessories.
The top rail section lets shooters mount long eye relief (LER) scopes or reflex dot sights. As an added benefit, the low-profile Picatinny rail is a see-through design, which allows you to use stock iron sights.
Unlike its competitors, the NcStar development team created this SKS gas tube scope mount with two set screws to secure the mount to the rear sight base for a reliable optics mounting platform.
This tube is manufactured just slightly longer than spec to allow adjustment for the many variations of the SKS. So if you are expecting a clean drop in the unit or are not comfortable with gunsmithing, then do not purchase this product.
The NcStar gas tube will need more than a few minutes of filing, but the result will be the tightest fit possible, entirely appropriate for mounting the optic, which will actually stay zeroed.
Occasionally you can encounter some gas tubes out of spec with a considerably larger inner tube diameter due to inconsistent NcStar quality control, but you can replace it without problems.
Best for the Money:
Tapco - SKS Gas Tube W/Handguard
As you might conclude by now, despite production differences in the SKS, all share a gas tube of the similar length, whereas only the length of handguard (Albanian) or end of the tube (Yugoslavian) varies.
Therefore, we have an aftermarket standard and Yugo SKS gas tubes to choose from. Tapco, the American Parts Company, is the longtime U.S. manufacturer of firearm accessories known for their AR, AK, and SKS replacement components.
The engineers at Tapco developed two types of gas tubes for SKS rifles, branded as standard and Yugo pattern to replace an aging or malfunctioning SKS gas tube.
The model SKS6601 comes in olive drab color and it is intended for use with Yugoslavian-made M59/66, a Simonov-pattern rifle. The front of the Yugo Zastava M59/66 gas tube is different as it has a flange, whereas all the others don't.
On the other hand, the railed gas tube is the same as standard SKS gas tubes and features steel construction and a composite handguard. The attached handguard is made from high-quality composite polymer and includes a lightweight polymer Picatinny rail for the tops of rifles that provides all the strength of aluminum while being much lighter.
Although the Tapco SKS Gas Tube with handguard is a quality addition to the Tapco lineup, this item shares the same flaws of this design. As the Tapco gas tube comes squared off on the rear, you will need to file it to fit. Moreover, because of the varying sizes of factory pistons, you might have to buy a TAPCO replacement gas piston.
As a side note, this Tapco gas tube counts as a US 922r-compliant part and comes with a Tapco lifetime warranty.
This versatile handguard is an essential addition for anyone upgrading their Yugo SKS platform rifle due to the lightweight and top-railed handguard for added flexibility. Additionally, this is an easy way to install a compliant part to your Yugoslavian made SKS, as this Tapco gas tube counts is U.S.-compliant.
Best from Tapco:
Tapco - SKS Gas Tube W/Handguard
The Tapco SKS gas tube with handguard comes in a black finish and represents a quality replacement for your old SKS gas tube and handguard. At the same time, you will get the improved functionality of your SKS rifle due to the new steel gas tube and high-quality composite polymer handguard with Picatinny rail.
As the best buy from Tapco, this gas tube assembly with model number SKS6632B combines steel and reinforced military grade composite for exceptional durability and lightness. The handguard section comes with nine integrated Picatinny rail slots, allowing you to mount any red dots or scout-style riflescopes.
Tapco’s SKS Gas Tube with handguard features a redesigned steel tube without a retaining clip or pin, making it stronger than the original and keeping the handguard securely in place by two steel roll pins.
Although designed as a replacement gas tube for the SKS platform, this is not a simple drop-in part, as in some cases it might require filing and sanding for a proper fit.
Due to the wide array of SKS variants, your factory piston may not be compatible with a new gas tube, meaning that you should buy another replacement gas piston.
This product is precision machined in the U.S.A. This gas tube carries the Tapco lifetime warranty and counts as one US Sec 922r-compliant part.
Best Yugo Gas Tube:
Tapco SKS Yugo Gas Tube W/Handguard
All SKS rifles are poorly-suited to optics, but if you want to go that way, Tapco has a whole series of gas tubes with handguards that provide a mounting platform. These gas tube assemblies come in several finishes and are offered either in a standard version or one that fits most Yugoslavian SKS models. While the standard Russian or Chinese SKS gas tubes are cylindrical, a gas tube for the Yugoslavian 59/66 SKS has a lip at the end to allow fitting over the gas valve.
Besides the SKS6632 models that fit every other model, the Tapco part number for the replacement Zastava Yugo gas tube and handguard is SKS6601.
Like other models, this product closely resembles the Tapco SKS Handguard from the SKS Intrafuse System. The gas tube is made of steel and the handguard features high-quality composite polymer construction.
Like all models from this series, it provides an integral Picatinny rail on top of the SKS, making a reliable mounting platform for accessories such as reflex sights or LER optics.
Though this railed gas tube with handguard is designed as a replacement gas tube for the Yugo SKS platform, it is not quite a simple drop-in part, but it may need some elementary gunsmithing and minor fitting.
Actually, you have to file just a small metal part of the top of the gas tube to get the retainer to close and hold it in place.
Since this part is manufactured in the U.S. by Tapco, it counts as a U.S. 922r-compliant part. It also has an overall black finish and a Tapco lifetime guarantee.
The standard-sized gas tube from Tapco is a quality replacement for an old and worn out SKS gas tube and handguard.
The Tapco Intrafuse, with part number SKS6632 is shipped with a replacement SKS gas tube machined from steel, an upper handguard constructed of high strength, reinforced composite, and an integrated nine-slot Picatinny rail made of polymer material reinforced with high strength fibers.
As this convenient Picatinny rail is molded directly into the handguard, it creates a stable mounting platform for optics, whereas it eliminates the need for additional mounting hardware.
While this gas tube assembly for the standard platform is a significant upgrade to your aging firearm, due to the inconsistent sizes of factory SKS pistons, you may be required to alter your original piston with a TAPCO replacement gas piston.
Although the manufacturer advertises this as a simple drop-in part, you should be prepared to file some material off the back of the tube to create a perfect fit.
With this well-designed gas system, your rifle will function properly and will meet the U.S. 922r compliance standards
The model branded as SKS6632 is finished in dark earth color and will fit all standard models except the Yugoslavian SKS models, which are longer in size and of a different pattern.
The TAPCO Intrafuse SKS gas tube not only looks good but adds some versatility with the top-mounted Picatinny rail offering a place for accessories such as scopes, red dots, or replacement iron sights.
You can also purchase the Tapco SKS Intrafuse railed gas tube as a part of the Tapco Fusion series stock set called an Intrafuse SKS Stock System.
How to Change Your SKS Gas Tube?
Designed to be used by conscripts and mobilized masses, Sergei Simonov's semi-automatic carbine is relatively simple for disassembling into its major components. Accordingly, the SKS gas tube is easy to replace, but there may be a degree of difficulty in removing the handguard pin at the rear of the gas tube, depending on the model of the rifle.
1. No matter the rifle type or manufacturer, the first step is to remove the handguard. That can be done by pivoting the small lever located on the right side of the rear sight assembly. When the handguard is loose, you can release it from the rear sight housing and pull out the gas block.
Note: the lever should be pulled only until the lower detent stops at the notch. Moving the bar past the lower detent will cause the operating rod and spring to fly out from their housing.
2. Now, you can install the front of the replacement gas cylinder onto the gas block and pivot the gas tube assembly down until it seats correctly into the rear sight housing.
3. In case you want to keep the gas tube and only replace an original wooden handguard, this is where it gets more complicated and will require extreme care and tedious work. You will have to apply some force with a hammer and a pin punch to the smaller side to extract the pin.
4. Finally, when you have placed new handguard in position, you can pivot the locking lever down until the lower detent is all the way down at the bottom of the groove.
Although simple for disassembly and assembly, SKS parts may require some fitting and adjustments. If you encounter any difficulty with locking the gas tube in place, you will probably need to file the rear block of the gas tube for proper fit. Both manufacturers and gun builders recommend the use of a metal file instead of any power devices such as a Dremel.
There are many YouTube clips describing upgrading an SKS and installing new gas tubes, but this video offers a full overview of what we have just described.
One of the most underappreciated Cold War rifles, SKS had the misfortune to be born at the same time as the iconic AK-47 assault rifle. The old humble SKS is actually a well-designed and well-made Cold War workhorse that fires the same round as the AK-47, but outside of the round, these two Russian firearms have hardly anything in common.
Since the SKS uses a traditional inline rifle stock, a milled receiver, and semi-automatic-only design, it comes with more in common with the American M14 than Russian AK-47.
This model features tighter tolerances than the AK-47, making it capable of hitting targets four out of every five shots at 400+ yards, with iron sights, of course.
While today, the official task has been reduced only to the role of “ceremonial arms” for which the SKS is extremely well-suited, in civilian hands, this robust design, even after 70 years can be very useful.
Making some crucial upgrades, like installing a replacement SKS gas tube onto your aging weapon will bring your weapon into the 21st century and extend its life for many new generations to come.