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Work order — Ruger AR-556

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: high.

Shop difficulty: Tier 2 of 3

72 parts, the standard AR-15 full strip. It needs several captive detents and plungers (takedown and pivot detents, buffer retainer, selector detent, bolt catch plunger), roll pins, and a hammer spring that only works one way round. These are common traps with common jigs, and nothing is timed. 72 parts (Complete rifle, standard handguard (72 line items; free-float supplement excluded)). Pew-Takedown's rating, not the manufacturer's.

Bench time: strip ~45 min, rebuild ~70 min (estimate). Actual: strip ______ rebuild ______

Special tools:

• AR armorer's wrench — Castle nut, barrel/muzzle
• upper and lower vise blocks — Holding receivers
• roll pin punches and starters (1/8, 3/32, 5/64 in) — Bolt catch, trigger guard, gas block roll pins
• pivot pin detent tool — Front pivot pin detent
• slave pin — Trigger/hammer reassembly

Watch for:

• The front pivot-pin detent and spring go in sideways under compression and launch across the room without a pivot-pin tool. (reassembly; ITS Tactical)
• A hammer spring fitted backwards can look right but will not detent the trigger pin. The result is light strikes and the pin walking out. (reassembly; Gun Tests)

1. Clear and make safe

1. Point the muzzle in a safe direction and keep your finger off the trigger.
2. Press the magazine release and remove the magazine.
3. Pull the charging handle fully to the rear and lock the bolt back with the bolt catch.
4. Visually inspect the chamber and magazine well, then physically feel the chamber to confirm it is empty.
   Warning: Check the magazine well as well as the chamber — a round can hang up there.
5. If the hammer is cocked, place the selector on SAFE.
6. Remove all live ammunition from the work area.

2. Disassemble

Manufacturer's video: Ruger® AR-556® Disassembly Tech Tip (RugerFirearms)
https://www.youtube.com/watch?v=qSiRy_QkHX8
Ruger® AR-556® Delta Ring Tech Tip (RugerFirearms)
https://www.youtube.com/watch?v=rxLnFn8UG-Y

Field Strip

1. Complete the Clear and Make Safe procedure and release the bolt forward.
2. From the left-hand side of the lower receiver, push the rear takedown pin to the right, then pull it from the right side until the detent stops further travel.
   Warning: Ruger's caution: the upper receiver will move forward once the pin is disengaged and can pinch your fingers if you are holding the magazine well. Hold the upper and lower together until you are ready to open the rifle.
   Tip: If the pin is stiff, Ruger sanctions using a punch and gently tapping with a hammer. It loosens with use.
3. Pivot the upper receiver forward on the front pivot pin.
   Tip: Tipping the upper forward on the front pivot pin is all Ruger's field strip requires. Driving the front pivot pin out as well fully separates the receivers, which is only needed to work on them separately.
4. Push the front pivot pin out to its captured position and separate the upper from the lower receiver.
5. Pull the charging handle partway rearward and withdraw the bolt carrier group.
6. Pull the charging handle down and out of its channel.
   Warning: The charging handle comes out after the carrier, never before.

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.

The manufacturer's full parts list (72 parts) is on the reference page.

4. Reassemble

Manufacturer's video: Ruger® AR-556® Reassembly Tech Tip (RugerFirearms)
https://www.youtube.com/watch?v=o3grmup0Jms

Reassembly

1. Insert the bolt into the carrier with the extractor oriented toward the ejection port side.
2. Push the bolt fully into the carrier, drop the cam pin into its hole, and rotate it 90 degrees.
   Warning: If the cam pin is not rotated, the firing pin will not seat. Never force the firing pin.
3. Drop the firing pin into the rear of the carrier, tail first, and let it seat fully.
4. Install the firing pin retaining pin. If it will not go in, the cam pin is missing or not rotated.
   Warning: This is the design’s built-in check. Do not defeat it.
5. Insert the charging handle into its channel and push it partway forward.
6. Insert the bolt carrier group into the charging handle’s track and slide both fully home.
7. Mate the upper to the lower, press the front pivot pin home, close the receivers, and press the rear takedown pin home.
8. Charge the rifle and 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: "Tighten the Delta Ring by turning it counterclockwise with your thumb and index finger (two-finger tight)." (Ruger AR-556 Owner’s Manual, PDF p. 37) "CAUTION: Do not over tighten the Delta Ring. Use two fingers only to tighten." (Ruger AR-556 Owner’s Manual, PDF p. 37)

Fit or check on rebuild

• Hammer spring orientation and pins flush — A reversed spring will not detent the trigger pin.
• Gas block alignment with port — A misaligned gas block short-strokes. Standard check.
• 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.

6. Function check

• Verify the rifle is unloaded with no magazine inserted before each step.
• Charge the rifle to cock the hammer, place the selector on SAFE, and press the trigger. The hammer must not fall.
• Move the selector to SEMI and press the trigger. The hammer should fall.
• Hold the trigger to the rear, charge the rifle, then release the trigger slowly and listen for the disconnector to release the hammer to the trigger.
• Press the trigger again. The hammer should fall.
• Insert an empty magazine, charge the rifle, and confirm the bolt locks back.

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

If it won't go back together

Sources

1. TM 9-1005-319-10: Rifle, 5.56mm, M16A2/M4 Carbine — U.S. Department of the Army primary
2. Ruger AR-556 Owner’s Manual — Sturm, Ruger & Co., Inc. primary
   https://ruger-docs.s3.amazonaws.com/_manuals/AR-556.pdf
3. DIY AR-15 Build: Pivot Pin Installation — ITS Tactical secondary
   https://www.itstactical.com/?p=10638
4. (Gunsmithing the AR-15 #2) The 30-Second AR Check — Gun Tests secondary
   https://www.gun-tests.com/?p=26007

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.