← All firearms · Printable work order

Mosin-Nagant M91/30

• easy
• Shop tier 1
• medium confidence
• Rifle
• surplus
• bolt action
• milsurp
• corrosive ammo
• historic

field strip ~2 min · reassembly ~4 min · detail strip ~20 min

Specifications

Model-specific safety

• Firing pin protrusion on this rifle is adjustable and MUST be set correctly. Too much protrusion causes pierced primers and slam fires; too little causes misfires. The issued combination tool has a gauge slot for exactly this purpose. If you disassemble the bolt, you must reset protrusion with a gauge.
• Surplus 7.62x54mmR is usually corrosively primed. Clean with a water-based solvent the same day you shoot.
• Newly imported rifles are often packed in cosmoline throughout, including the bolt and firing pin channel. Clean thoroughly before firing.
• The bolt is removed by pressing the trigger while withdrawing it. Confirm the chamber and magazine are empty before you do that.
• These rifles are 80 to 100 years old. Have the headspace checked by a gunsmith before firing a rifle of unknown history.

Under spring tension

• Mainspring inside the bolt
• Magazine follower spring

Easily lost parts

Bolt connector bar · Bolt head · Extractor · Interrupter/ejector

Tools

Shop difficulty

Shop tier 1 Tier 1 — easy among rifles and carbines, for the full job: strip to the parts that get coated and put it back together working. Only about 34 numbered parts (American Rifleman legend), held by screws and simple springs, and it strips with a screwdriver and punches. The fiddly bits are a bolt that must be re-indexed and gauged for firing-pin protrusion, and fragile band springs. None of these needs a held-under-tension pin or timing.

Parts: 34 numbered parts (complete Mosin-Nagant Model 1891 family rifle (article states the instructions apply to all patterns; the M91/30 is named as the most common) per the American Rifleman exploded-view 'Parts Legend', ke), from Exploded View: Mosin-Nagant Model 1891 Family Of Rifles (American Rifleman, July 2016, p. 73), by Ian McCollum — NRA / American Rifleman, p. 73 (single-page PDF linked from https americanrifleman.org [6].

Bench time: about 35 min to strip, 50 min to rebuild (estimate). Detail strip of bolt, magazine/trigger guard, bands, sights. Rebuild time is driven by indexing the firing pin to its witness line and gauging protrusion.

Small parts: 3 pins, 5 springs, 0 detents or plungers (counted by name in the same legend (line items). Pins: 19 trigger hinge pin, 26 follower hinge pin, 32 follower hinge pin (upper) (4 firing pin not counted). Springs: 3 firing pin spring, 11 ejector s)

What comes off for coating

• Stock: barrel bands and band springs, handguard, cleaning rod, tang screws, buttplate, action (with shims)
• Bolt: cocking piece, firing pin and spring, bolt head, guide bar, extractor — firing pin protrusion gauge (combination tool)
• Magazine / trigger guard: floorplate and latch, follower and springs, trigger and pin, sear/trigger spring
• Receiver / barrel: interrupter/ejector and spring, rear sight leaf, slide, spring, front sight (drift)

Special tools

• Mosin combination tool / firing-pin protrusion gauge — Setting firing pin protrusion after bolt reassembly
• hollow-ground screwdrivers — Staked military screws
• small C-clamp — Compressing the rear sight leaf spring

Known pain points

• The bolt must be reassembled with the cocking piece, guide bar and bolt head in one specific alignment, and the firing pin screwed back to its witness mark. (reassembly)
  Source: Exploded View: Mosin-Nagant Model 1891 Family Of Rifles — American Rifleman (NRA) americanrifleman.org [4] — “First, note the witness line at the rear of the cocking piece—this must be put into the same position when the bolt is reassembled (Fig. 6).”
• The firing pin is under mainspring tension while it is unscrewed from the cocking piece. (disassembly)
  Source: Exploded View: Mosin-Nagant Model 1891 Family Of Rifles — American Rifleman (NRA) americanrifleman.org [4] — “The firing pin is under spring tension, and will jump slightly when fully unscrewed.”
• Firing-pin protrusion has to be re-checked with a gauge after the bolt is reassembled, or the rifle misfires or pierces primers. (reassembly)
  Source: Mosin Nagant Rifle Exploded Views and Disassembly — 7.62x54r.net (hosted by thinlineweapons.com) thinlineweapons.com [5] — “After fully assembling the bolt, decock it, make sure the bolt head is tight against the connector bar and check the firing pin protrusion with a gauge.”
• The barrel-band retaining springs in the stock are delicate and break if pulled out by the leaf. They must be drifted out from the other side. (disassembly)
  Source: Mosin Nagant Rifle Exploded Views and Disassembly — 7.62x54r.net (hosted by thinlineweapons.com) thinlineweapons.com [5] — “These springs are delicate and can be easily broken if pulled out by the leaf.”
• Loose parts on the way out of the stock: the trigger pin is retained only by the stock, and tang/recoil-lug shims must be kept and put back in place. (both)
  Source: Mosin Nagant Rifle Exploded Views and Disassembly — 7.62x54r.net (hosted by thinlineweapons.com) thinlineweapons.com [5] — “The trigger pin is held in place only by the stock and if it is loose can fall out upon removal of the action.”

Fit or check on rebuild

• Firing-pin protrusion — Incorrect protrusion causes misfires or pierced primers.
  Source: Mosin Nagant Rifle Exploded Views and Disassembly — 7.62x54r.net (hosted by thinlineweapons.com) thinlineweapons.com [5] — “check the firing pin protrusion with a gauge”
• Tang screw torque / shims — Loose action screws cost accuracy, and shims must go back in place.
• 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

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.

What the manufacturer does say: The official military manuals give no torque value. They say: "67. Заканчивая осмотр винтовки в собранном виде, проверить, правильно ли довинчены винты хвостовой и упора. Чрезмерное завинчивание винта упора может повлечь за собой расшатывание угольника в соединении со щеками магазинной коробки, особенно если магазинная коробка верхним краем упирается снизу в ствольную коробку." [translation by this project: "67. On finishing inspection of the assembled rifle, check that the tang screw and the recoil screw are properly screwed home. Over-tightening the recoil screw can loosen the trigger-guard plate's joint with the sides of the magazine box, especially if the top edge of the magazine box bears against the underside of the receiver."] (Наставление по стрелковому делу (НСД-38). Винтовка обр. 1891/30 г. (1941 printing), p. 58 (PDF p. 62), ст. 67) "д) неравномерно завинчены винты упора и хвостовой (недовинчены или перетянуты) — пули уклоняются вверх или вниз;" [translation by this project: "e) the recoil and tang screws are unevenly tightened (under-tightened or over-tightened) — bullets deviate upward or downward;"] (Наставление по стрелковому делу (НСД-38). Винтовка обр. 1891/30 г. (1941 printing), p. 77 (PDF p. 81), ст. 120)

Function check

• Verify the rifle is unloaded before each step.
• Cycle the bolt and confirm it cocks on opening and closes fully.
• With the bolt closed and cocked, pull the cocking piece back and rotate it to the safe position. Confirm the trigger is blocked.
• Return the safety and press the trigger — the firing pin should release with a firm snap.
• Confirm firing pin protrusion with the gauge if the bolt was apart.
• Load five dummy rounds and confirm the interrupter feeds them one at a time without rim lock.

Maintenance

Lubrication points

• Bolt lugs and raceways
• Cocking cam surfaces
• Extractor
• Trigger and sear contact

Cleaning notes

Clean from the breech with a bore guide whenever possible. After corrosive ammunition, flush the bore and bolt face with hot soapy water or a water-based solvent the same day, dry completely, and oil. Keep the firing pin channel dry.

Suggested inspection interval: roughly every 300 rounds. This is a general guideline, not a manufacturer specification.

Wear parts to inspect

Firing pin tip and protrusion · Extractor · Bolt lugs · Interrupter/ejector · Crown (for cleaning rod wear)

Common issues

Also covers

The procedures above are reported to apply to: Mosin-Nagant M38 · M44 Carbine · Finnish M39 (with differences) · Chinese Type 53. Verify against the manual for your specific model.

Similar manual of arms

• SKS

Sourcing