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Work order — Heckler & Koch G3 / PTR-91

Taking the firearm apart for a job such as refinishing, and putting it back together to specification. Generated from the Pew-Takedown entry last updated 2026-10-29. Confidence: medium.

Shop difficulty: Tier 2 of 3

PTR's list has 71 key numbers (76 pieces) including the trigger pack. The barrel stays pressed and pinned in the receiver, so the work is the trigger pack (hammer, pressure fork, springs), the bolt head rollers, the cocking support roll pin, and a rear sight with loose balls and springs. Bolt gap must be measured after reassembly. Several traps but nothing timed. 71 parts (PTR-91 GI complete rifle incl. trigger pack internals and bolt group (76 pieces)). Pew-Takedown's rating, not the manufacturer's.

Bench time: strip ~55 min, rebuild ~80 min (estimate). Actual: strip ______ rebuild ______

Special tools:

• HK rear sight adjustment tool — Rear sight drum removal
• Roll-pin punches (2 mm, 2.5 mm, 4 mm) — Clamping sleeves in the trigger pack, mag catch, front sight, cocking support
• Feeler gauges — Bolt gap
• Flash hider wrench — Flash hider/spring ring

Watch for:

• PTR stops the owner at the bolt group and sends any further strip (trigger pack, cocking support, sights) to a gunsmith. (both; PTR Industries, Inc.)
• The bolt head has to be clocked to the locking lever, rollers squeezed in and turned to the slot before the carrier goes back. (reassembly; PTR Industries, Inc.)
• The rear sight drum sits on loose springs and plungers, and the sight base on a ball and spring; they are not captive and fly when the drum comes off. (both; Heckler & Koch, Inc. International Training Division)
• The cocking handle support is held by a clamping sleeve (roll pin) that only lines up with both holes in one handle position. (both; Heckler & Koch, Inc. International Training Division)
• HK's own armorer kit for the G3 includes straightening mandrels for the stamped receiver and cocking tube, plus gauges for symmetry and headspace. (both; Heckler & Koch)

1. Clear and make safe

1. Point the muzzle in a safe direction and keep your finger off the trigger.
2. Place the selector on safe if the design allows it with the action in its current state.
3. Press the magazine release and remove the magazine.
4. Pull the charging handle fully to the rear and lock the action open if the rifle has a hold-open.
5. Inspect the chamber and magazine well with a light, then physically confirm the chamber is empty.
   Warning: Look and feel. Both, every time.
6. Remove all live ammunition from the work area.

2. Disassemble

Field Strip

1. Complete the Clear and Make Safe procedure with the selector on safe.
2. Push out the two push pins at the rear of the receiver and withdraw them.
3. Pull the buttstock straight back and off the rear of the receiver.
   Warning: The recoil spring assembly is under compression — control it.
4. Pivot the trigger group down and off the receiver.
5. Withdraw the recoil spring assembly from the rear of the receiver.
6. Pull the cocking handle fully rearward and withdraw the bolt carrier group out of the rear of the receiver.
7. Separate the bolt head from the carrier, remove the locking piece, and push the rollers out of the bolt head from the inside.
   Warning: Keep the rollers and locking piece with their own bolt. Inspect the rollers for flats and chipping.
8. Remove the handguard by pushing out its retaining pin.

3. Refinish

The components the procedures above separate. Coating, masking and cure are outside this database; follow your coating system's instructions. A part the manufacturer marks "factory fit" should not be swapped or reworked.

No manufacturer statement of materials or finish is recorded. Identify each part's material before choosing prep and cure.

4. Reassemble

Reassembly

1. Reinstall the handguard and its pin.
2. Reassemble the bolt: rollers into the bolt head, locking piece into the carrier, bolt head onto the carrier.
3. Insert the bolt carrier group into the rear of the receiver, engaging the cocking handle, and slide it forward.
4. Insert the recoil spring assembly into the rear of the receiver.
5. Pivot the trigger group into place and align its pin holes.
6. Slide the buttstock onto the rear of the receiver.
7. Insert both push pins and press them fully home.
   Warning: Both pins fully seated. A stock that is not pinned can come off under firing.
8. Pull the cocking handle fully back and release it sharply, then perform the function check.

5. Torque

No manufacturer torque values are recorded for this firearm.

Notes: The manufacturer's documents give no torque value. They say: "Once the correction has been completed, tighten the Phillips head rear sight clamping screw back down." (PTR Roller-Delayed Blowback Weapon Systems Owner's Manual, Models .308 and 7.62x39, PDF p. 10 (windage adjustment))

Fit or check on rebuild

• Bolt gap — Measured with feeler gauges after reassembly; out of range means roller/locking piece work
• Rear sight zero — The drum and base come off and the rifle must be re-zeroed
• Trigger function — Pressure fork and hammer spring seating checked with a function check

6. Function check

• Verify the rifle is unloaded with no magazine inserted before each step.
• Pull the cocking handle fully rearward and release it sharply. The bolt should go fully into battery.
• With the selector on safe, press the trigger. The hammer must not fall.
• Move to semi-automatic, cock the action, and press the trigger. The hammer should fall.
• Hold the trigger back, cock the action, and release to feel the disconnector reset.
• Confirm both push pins are seated and the stock and trigger group are secure.
• If the bolt does not go fully into battery, do not fire. Have the bolt gap checked.

If any check fails, the firearm is not safe to fire. Stop and see a licensed gunsmith.

Sources

1. Heckler & Koch G3 Rifle Operator’s and Armorer’s Manual — Heckler & Koch GmbH primary
2. PTR Roller-Delayed Blowback Weapon Systems Owner's Manual, Models .308 and 7.62x39 — PTR Industries, Inc. primary
   https://www.ptr-us.com/wp-content/uploads/2023/01/PTR-.308-and-7.62x39-Owners-Manual.pdf
3. MP-5 Armorers Instruction — Heckler & Koch, Inc. International Training Division primary
   https://archive.org/download/MManuals/HkMp5ArmorersManual.pdf
4. G3 Armorer's Manual, Instructions for Maintenance and Repair, Cal. 7.62 mm x 51 — Heckler & Koch primary
   https://archive.org/download/lots-of-gun-pdfs-firearms-manuals/Gun%20PDFs/hk_g3.pdf

Educational guide only. Some information comes from non-authoritative sources. Always consult your manufacturer's manual and a licensed gunsmith. Verify your firearm is unloaded before every procedure. Full disclaimer: https://github.com/Fundamental-build-LLC/Pew-Takedown

Legal notice: this material is third-party information compiled from sources of varying reliability and is provided for general informational and educational purposes only. It is not gunsmithing, technical, safety or legal advice, it is not verified or endorsed by any manufacturer, and it must not be taken as fact. Any work on a firearm beyond the routine field stripping described in its own owner's manual should be performed only by a licensed and insured gunsmith. You use this material entirely at your own risk. Fundamental Build LLC and the project's contributors make no warranty of any kind and accept no liability for death, injury, damage or loss arising from its use. Full terms: LEGAL.md.