← All firearms · Printable work order
SKS
- easy
- Shop tier 2
- high confidence
- Rifle
- surplus
- short stroke piston
- fixed magazine
- corrosive ammo
- slam fire risk
field strip ~3 min · reassembly ~4 min · detail strip ~30 min
Specifications
- Manufacturer
- Tula Arms Plant
- Origin
- Soviet Union
- Category
- Rifle
- Action
- Gas, short-stroke piston
- Calibers
- 7.62x39mm
- Capacity
- 10 rounds in the fixed magazine on most variants
- Production
- 1945–1955 (surplus)
- Also known as
- Samozaryadny Karabin sistemy Simonova, Type 56 Carbine (Chinese), Yugo M59/66
Model-specific safety
- SKS slam fires are a real and well-documented hazard. The firing pin is free-floating, and if its channel is packed with hardened cosmoline or fouling, the pin can stick forward and fire a round as the bolt closes — sometimes out of battery, sometimes in full-auto bursts. Before firing any SKS, especially a newly imported one, strip the bolt and clean the firing pin channel until the pin rattles freely.
- Do not skip the bolt cleaning on a surplus rifle. Cosmoline is not just on the outside.
- Most SKS variants have a fixed magazine that is unloaded through the floorplate or by cycling. Verify both the magazine and the chamber are empty.
- Yugoslav M59/66 variants have a grenade launcher and a gas cutoff valve. If the gas valve is closed, the rifle will not cycle — this is a configuration, not a malfunction.
- Most surplus ammunition for this rifle is corrosively primed. Plan to clean with a water-based solvent the same day you shoot.
Under spring tension
- Recoil spring assembly
- Magazine spring
- Hammer spring in the trigger group
Easily lost parts
Firing pin · Firing pin retaining pin · Receiver cover latch · Gas piston and its spring
Tools
| Tool | Required | Used for | Substitute |
|---|---|---|---|
| Cleaning kit tool from the buttstock trap | Optional | The issued combination tool handles most disassembly needs. |
Shop difficulty
Shop tier 2 Tier 2 — moderate among rifles and carbines, for the full job: strip to the parts that get coated and put it back together working. 55 numbered parts (American Rifleman legend). The trigger group is the trap: the hammer is under heavy spring pressure and has to be levered out with a bar in a padded vise, and the group is hard to refit into the stock. There is no timing, and the rest goes together in order.
Parts: 71 numbered parts (complete SKS (Type 56 / Simonov 7.62x39mm autoloading carbine) per the Gun Digest exploded drawing legend, keys 1-71: gas system, receiver and barrel, bolt group, trigger group, fixed magazine with fo), from The Gun Digest Book of Exploded Gun Drawings (975 isometric views) — '7.62x39mm Autoloading Carbine' (SKS) — Gun Digest Books / Krause Publications (scan on archive.org), p. book p. 860 (PDF page 861) archive.org [4].
Bench time: about 40 min to strip, 60 min to rebuild (estimate). Receiver cover, bolt and carrier, gas piston and tube, trigger group detail strip (hammer out in vise), stock, bayonet, sights.
Small parts: 12 pins, 10 springs, 0 detents or plungers (counted by name in keys 1-71 of the same legend (line items). Pins: 4 handguard ferrule pin, 15 hold-open latch pin, 21 latch pin, 38 hinge pin, 43 latch stop pin, 45 disconnector hinge pin, 46 trigge)
What comes off for coating
- Receiver: receiver cover and takedown latch, recoil spring assembly, bolt carrier and bolt, gas cylinder/handguard and piston, rear sight, front sight (drift)
- Bolt: firing pin and retainer, extractor and spring
- Trigger group: hammer and spring (levered out), trigger, sear, disconnector, safety and spring, trigger guard catch — padded vise, metal bar
- Stock: magazine assembly, bayonet and pivot screw, buttplate
Special tools
- padded vise — Holding the trigger guard
- metal bar — Forcing the hammer out
- SKS front sight tool — If the front sight is adjusted
Known pain points
- Stripping the trigger guard means releasing a heavily sprung hammer and forcing it out with a metal bar in a padded vise. (disassembly)
Source: Exploded View: SKS Carbine — American Rifleman (NRA) americanrifleman.org [3] — “Push down on the disconnector (49) and pull the trigger (44) to release the hammer. (Caution: Be careful as the hammer is under heavy spring pressure.) Use a metal bar as shown (FIG. 4) to force the hammer out.” - The trigger group has to hook its two front pins into the magazine notches, then be forced into the stock against a stiff catch. (reassembly)
Source: Exploded View: SKS Carbine — American Rifleman (NRA) americanrifleman.org [3] — “Note that reinstallation of the trigger assembly can be difficult.” - The firing pin has no spring. Any preservative grease left in its channel after refinishing can let it stick forward and fire as the bolt closes. (reassembly)
Source: Exploded View: SKS Carbine — American Rifleman (NRA) americanrifleman.org [3] — “The gun’s design does not include a firing pin spring, and excessive grease in the firing pin channel can cause the pin to stick in the forward position and fire unexpectedly when a cartridge is chambered.”
Fit or check on rebuild
- Firing pin moves freely (no grease) — There is no firing pin spring, and a stuck pin can fire as the bolt closes.
Source: Exploded View: SKS Carbine — American Rifleman (NRA) americanrifleman.org [3] — “It is important to ensure that the firing pin moves freely in the bolt when the gun is disassembled.” - Function check (safety, trigger reset, feeding, extraction) — Standard after any detail strip. No single source.
- Re-zero sights or scope — Sights and optics come off for coating, and point of impact must be re-confirmed. This is a standard check, so no source.
This is Pew-Takedown's rating, not the manufacturer's. How tiers are rated. Forum reports are owners' experience, not specifications.
Procedures
Clear and Make Safe
Clear & Make Safe- Point the muzzle in a safe direction and keep your finger off the trigger.
- Rotate the safety lever down to the fire position so the bolt can travel fully.
- Pull the bolt fully to the rear and lock it back on the bolt hold-open.
- Press the magazine floorplate latch at the rear of the magazine and swing the floorplate down to dump any rounds from the fixed magazine.TipOn a detachable-magazine variant, remove the magazine instead.Removed at this step:
Rounds in the magazine - Inspect the chamber and the magazine with a light, then physically confirm the chamber is empty.
- Close the floorplate, ease the bolt forward, and remove all ammunition from the work area.
Field Strip
Field Strip- Complete the Clear and Make Safe procedure.
- Rotate the receiver cover retaining pin lever on the right rear of the receiver upward 90 degrees, then pull the pin out to the right.Removed at this step:
Receiver cover retaining pin - Pull the receiver cover rearward and lift it off.WarningThe recoil spring assembly is under compression behind it. Keep a hand over the rear of the receiver.Removed at this step:
Receiver cover - Withdraw the recoil spring assembly from the bolt carrier.Removed at this step:
Recoil spring assembly - Pull the bolt carrier and bolt fully to the rear and lift them up and out of the receiver.Removed at this step:
Bolt carrierBolt - Separate the bolt from the carrier by sliding it forward and out.
- Rotate the gas tube lever on the right side of the rear sight base upward, then lift the gas tube and upper handguard up and off.Removed at this step:
Gas tube and upper handguard - Withdraw the gas piston from the gas tube.Removed at this step:
Gas piston - To remove the trigger group, press the trigger group latch at the rear of the trigger guard and lift the assembly out of the stock.TipThe safety must be in the fire position.Removed at this step:
Trigger group
Clean the Firing Pin Channel (do this before firing a surplus rifle)
Maintenance tools requiredThe single most important maintenance procedure on this rifle. Skipping it is how slam fires happen.
- With the bolt removed from the rifle, push out the firing pin retaining pin from the side of the bolt.Removed at this step:
Firing pin retaining pin - Tip the bolt and let the firing pin slide out of the rear.WarningIf the firing pin will not move freely, it is stuck. That is exactly the condition that causes slam fires.Removed at this step:
Firing pin - Clean the firing pin and the channel inside the bolt with solvent until every trace of cosmoline and fouling is gone. Degrease thoroughly.
- Reinstall the firing pin dry. Do not oil the firing pin channel.WarningOil in the channel collects fouling and can congeal, recreating the stuck-pin condition.
- Reinstall the retaining pin, then shake the bolt next to your ear. You should clearly hear and feel the firing pin rattle freely.WarningIf it does not rattle, do not fire the rifle. Clean it again or have it inspected.
Reassembly
Reassembly- Install the trigger group by hooking its front into the receiver and pressing the rear up until the latch engages.
- Insert the gas piston into the gas tube, then set the gas tube and handguard onto the barrel and rotate the lever down to lock.
- Fit the bolt into the carrier, then set the assembly into the receiver rails and slide it forward.
- Insert the recoil spring assembly into the bolt carrier and seat its rear end in the receiver.
- Slide the receiver cover on from the rear, press it down, and insert the retaining pin, rotating its lever down to lock.WarningConfirm the pin lever is rotated fully down. A loose cover can come off under recoil.
- Cycle the action several times and perform the function check.
Torque specifications
No sourced torque values from the manufacturer are recorded for this firearm. Where a fastener has a specified torque — action screws, scope bases, muzzle devices, barrel nuts — get it from the manufacturer or a gunsmith rather than estimating it.
Function check
- Verify the rifle is unloaded, chamber and magazine, before each step.
- Shake the assembled bolt before installing it — the firing pin must rattle freely.
- Cycle the bolt by hand and confirm it locks and returns to battery.
- With the safety engaged, press the trigger. Nothing should happen.
- Disengage the safety, cycle the bolt, and press the trigger. The hammer should fall.
- Confirm the bolt hold-open engages on an empty magazine.
- Confirm the magazine floorplate latches securely closed.
Maintenance
Lubrication points
- Bolt lugs and bolt body
- Carrier rails
- Gas piston (very light film only)
- Trigger group pivots
Cleaning notes
Corrosive primers leave salts that rust a bore within a day or two in humid conditions. After shooting surplus ammunition, flush the bore, gas tube, gas piston, and bolt face with hot soapy water or a water-based solvent, dry completely, then oil. Keep the firing pin channel dry and clean at all times.
Suggested inspection interval: roughly every 500 rounds. This is a general guideline, not a manufacturer specification.
Wear parts to inspect
Firing pin (free movement is the key check) · Extractor and extractor spring · Recoil spring · Gas piston · Bolt lugs
Common issues
| Symptom | Likely cause | What to do |
|---|---|---|
| Rifle fires more than one round per trigger press, or fires as the bolt closes | Firing pin stuck forward in a fouled or cosmoline-packed channel | Stop firing immediately and unload the rifle. Strip the bolt, clean the firing pin channel completely, and reinstall dry. Do not fire until the pin rattles freely. see a gunsmith |
| Rifle will not cycle (Yugoslav M59/66) | Gas cutoff valve closed for grenade launching | Rotate the gas valve to the open position. |
| Rust appearing within days of shooting | Corrosive primer residue | Clean with a water-based solvent the same day, dry, and oil. |
Also covers
The procedures above are reported to apply to: Chinese Type 56 Carbine · Yugoslav M59 and M59/66 (with gas valve differences) · Romanian, Albanian, and Russian SKS variants. Verify against the manual for your specific model.
Similar manual of arms
Legal notes
Sourcing
- Confidence
- high — Cross-checked against a primary source such as the manufacturer's manual or an issuing military technical manual.
- Verification
- Checked against an armorer/technical manual
- Last updated
- 2026-10-29
References
Every source this page draws on, with its web address so you can read it yourself. Numbers in brackets elsewhere on the page point here.
- [1] 7.62mm Simonov Self-Loading Carbine (SKS) Operator's Manual — USSR Ministry of Defence military technical manual primary source
- [2] Small Arms Identification and Operation Guide — Eurasian Communist Countries — U.S. Defense Intelligence Agency military technical manual secondary source
- [3] Exploded View: SKS Carbine — American Rifleman (NRA) website secondary source
https://www.americanrifleman.org/content/exploded-view-sks-carbine/ (checked 2026-10-29) - [4] The Gun Digest Book of Exploded Gun Drawings (975 isometric views) — '7.62x39mm Autoloading Carbine' (SKS) — Gun Digest Books / Krause Publications (scan on archive.org) website secondary source
https://archive.org/download/the-book-of-exploded-gun-drawings-975-isometric-views/The%20Book%20of%20Exploded%20Gun%20Drawings%20-%20975%20Isometric%20Views.pdf (checked 2026-10-29)
Notes: The slam fire hazard is documented in manufacturer and military sources and is widely reported by owners of imported rifles. Treat the firing pin channel cleaning as mandatory, not optional.