{ "apiVersion": 1, "kind": "work-order", "purpose": "Taking the firearm apart for a job such as refinishing, and putting it back together to specification.", "firearm": { "slug": "daniel-defense-ddm4", "name": "Daniel Defense DDM4", "manufacturer": { "id": "daniel-defense", "name": "Daniel Defense" }, "category": "rifle", "action": "gas-operated-direct-impingement", "calibers": [ "5.56x45mm NATO" ], "alsoKnownAs": [ "DDM4 V7", "DDM4 V11" ], "coversAlso": [], "page": "firearms/daniel-defense-ddm4.html", "bundle": "api/v1/firearms/daniel-defense-ddm4.json", "lastUpdated": "2026-10-29" }, "notices": [ "Daniel Defense limits owner disassembly: Field strip: receivers apart, bolt carrier group and charging handle out, bolt carrier stripped, buttstock off, buffer and action spring out. Handguard removal goes to a gunsmith." ], "disclaimer": { "headline": "Read this before you use anything here.", "points": [ "This is a guide, not an authority. Entries are compiled from manufacturer manuals, technical manuals, published references, and community knowledge. Some of it comes from sources that are not authoritative, and some of it may simply be wrong.", "Always consult the manufacturer's manual for your specific firearm and serial-number range. Manufacturers change designs mid-production without renaming the model. The manual that shipped with your firearm outranks anything on this site.", "Consult a licensed gunsmith for anything beyond routine field stripping and cleaning, for any firearm you are unsure about, and for any procedure marked as gunsmith-recommended here.", "Treat every firearm as loaded. Verify it is unloaded, with the magazine removed and the chamber physically and visually checked, before any procedure in this database. Point it in a safe direction the entire time.", "Disassembly can damage a firearm or injure you. Springs are under tension, parts can launch, and reassembling a firearm incorrectly can make it unsafe to fire in a way that is not obvious from the outside. If a reassembled firearm does not pass a function check, stop and see a gunsmith.", "Torque values are shown in two groups. Values from the manufacturer or the issuing military are shown as such, with the document they came from. Values reported by anyone else — parts makers, gunsmithing publishers, articles, forums — are shown separately with who said them, how reliable that source is, and their exact words. Those are not specifications. Confirm any torque value with the manufacturer or a licensed gunsmith before relying on it.", "Nothing here is legal advice. Firearms law varies by country, state, and city, and some modifications or configurations are regulated or prohibited. You are responsible for knowing and following the law where you are.", "No warranty of any kind. Contributors and maintainers accept no liability for damage, injury, or loss arising from use of this material." ], "page": "disclaimer.html", "legal": { "summary": "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.", "page": "legal.html", "notice": "https://github.com/Fundamental-build-LLC/Pew-Takedown/blob/main/LEGAL.md" } }, "sourcing": { "confidence": "high", "verification": "armorer-manual-verified" }, "manufacturerDisassembly": { "status": "limited", "limit": "Field strip: receivers apart, bolt carrier group and charging handle out, bolt carrier stripped, buttstock off, buffer and action spring out. Handguard removal goes to a gunsmith.", "statement": "Daniel Defense says not to strip the rifle further than the manual describes; additional maintenance is referred to its servicing section, handguard removal to a qualified gunsmith, and maintenance beyond the manual to a qualified gunsmith.", "source": { "title": "Daniel Defense DDM4 / DD5 Safety & Maintenance Instructions (German/English), section 5.1 Stripping for Cleaning (Daniel Defense manual, copy hosted by ManualShelf)", "publisher": "Daniel Defense", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ddm4/safety-maintenance-instructions-german-english/page-30.html", "page": "28", "pdfPage": null, "pageUrl": null, "quote": "IMPORTANT: DO NOT STRIP YOUR FIREARM FURTHER THAN PREVIOUSLY DESCRIBED. IF ADDITIONAL MAINTENANCE IS REQUIRED, SEE “SERVICING AND REPAIRING” LATER IN THIS INSTRUCTION MANUAL." } }, "recalls": [], "shopTier": { "tier": 2, "group": "rifle", "rating": "Pew-Takedown editorial rating (1 easy – 3 hardest), not the manufacturer's", "reason": "An AR-15: about 82 labelled parts across DD's upper, lower and bolt carrier drawings, with the bolt as one assembly. It has the same AR traps (pivot and takedown detents, roll pins, port cover spring, hammer spring), plus the DD rail, which bolts to its own barrel nut and which DD tells owners to leave to a gunsmith.", "confidence": "high", "partCount": { "value": 82, "kind": "line-items", "covers": "DDM4 V1 upper (39 callouts), lower (37) and bolt carrier group (7, bolt as an assembly), counted from DD's parts illustrations; the complete BCG callout on the upper drawing is not counted twice", "basis": "manufacturer-diagram", "source": { "title": "Daniel Defense DD4 / DDM4 / DD5 Rifle Manual (2016, Rev 3.1)", "publisher": "Daniel Defense", "reliability": "primary", "url": "https://308ar.com/wp-content/uploads/2017/03/Daniel-Defense-DD4-DD5-Rifle-Manual.pdf", "page": "pp. 37, 38, 42 (6.1, 6.2, 6.6)", "pdfPage": null, "pageUrl": null, "quote": "DDM4 V1 SHOWN. SOME PARTS VARY BY PRODUCT." } }, "painPoints": [ { "issue": "The front pivot pin and rear takedown pin each sit on a spring-loaded detent that launches when the pin comes out; reinstalling the pivot pin means holding the detent down while the pin goes in, which is the classic AR lower trap.", "during": "both", "source": { "title": "AR Lower Receiver Build: Pivot Pin Installation", "publisher": "Shooting Illustrated (NRA)", "reliability": "secondary", "url": "https://www.shootingillustrated.com/content/ar-lower-receiver-build-pivot-pin-installation/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "The detent and spring will fly out and you will be spending a lot of time on your knees looking for them." } }, { "issue": "The TM has the armorer use a pivot pin tool to compress the detent, and warns to catch the detent and spring as the pin comes out.", "during": "both", "source": { "title": "TM 9-1005-249-23&P, Rifle, 5.56mm, M16 and M16A1 (unit and direct support, incl. RPSTL)", "publisher": "Department of the Army", "reliability": "primary", "url": "https://archive.org/download/ArmyTechnicalManualforM16Rifle-Tm9-1005-249-23p/Manual-Tm9-1005-249-23p_djvu.txt", "page": null, "pdfPage": null, "pageUrl": null, "quote": "Catch detent and spring as pivot pin is" } }, { "issue": "The bolt catch and trigger guard roll pins mar the receiver unless the receiver is taped and supported and a roll-pin starter punch is used.", "during": "both", "source": { "title": "TFB Armorer's Bench: Complete AR15 Assembly - Lower Receiver", "publisher": "The Firearm Blog", "reliability": "secondary", "url": "https://www.thefirearmblog.com/blog/2022/07/31/tfb-armorers-bench-complete-ar15-assembly-lower-receiver/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "Installing the bolt catch roll pin can be cumbersome and in the wrong hands, aesthetically destructive." } }, { "issue": "Daniel Defense says the rail/handguard (bolt-up system on its own barrel nut) should come off only at a gunsmith, with DD's torque specs.", "during": "both", "source": { "title": "Daniel Defense DD4 / DDM4 / DD5 Rifle Manual (2016, Rev 3.1)", "publisher": "Daniel Defense", "reliability": "primary", "url": "https://308ar.com/wp-content/uploads/2017/03/Daniel-Defense-DD4-DD5-Rifle-Manual.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "If removal of handguard is deemed necessary, please take firearm to a qualified and competent gunsmith." } } ], "minutes": { "strip": 40, "rebuild": 65, "basis": "estimated", "note": "Estimate: same as a generic AR-15 plus the DD rail (bolt-up plate and screws) and fixed front sight base taper pins on V1; rebuild adds the DD rail torque and barrel-nut indexing.", "source": null }, "stripScope": [ { "assembly": "Lower receiver", "removes": [ "pistol grip and screw (selector detent and spring)", "safety selector", "takedown pin, detent and spring", "pivot pin, detent and spring", "hammer, hammer spring and pin", "trigger, trigger spring, disconnector and spring, pin", "bolt catch, plunger, spring and roll pin", "magazine catch, spring and button", "trigger guard and roll pin", "buffer, buffer spring, buffer retainer and spring", "stock, castle nut, end plate, receiver extension" ], "tools": [ "roll-pin punches/starters", "pivot pin detent tool", "castle nut wrench" ] }, { "assembly": "Upper receiver", "removes": [ "charging handle", "bolt carrier group (firing pin, retaining pin, cam pin, bolt, extractor, spring, insert, ejector, ejector spring and pin", "ejection port cover, pin, spring and clip", "forward assist, spring and pin", "rear sight", "handguard/rail", "gas block or front sight base and pins, gas tube and pin", "DD bolt-up rail, plate and screws; barrel nut and barrel", "muzzle device and crush washer" ], "tools": [ "upper receiver vise block", "armorer's/barrel nut wrench", "torque wrench", "bench block", "taper-pin punch" ] } ], "hardware": { "pins": 15, "springs": 15, "detents": 6, "basis": "counted from the DD parts illustrations in partCount ('SPS' rows counted as spring pins)" }, "specialTools": [ { "tool": "Upper receiver vise block / reaction rod", "usedFor": "Holding the upper for barrel nut and muzzle device work" }, { "tool": "AR armorer's wrench (barrel nut/castle nut)", "usedFor": "Barrel nut and receiver extension castle nut" }, { "tool": "Torque wrench (ft-lb and in-lb)", "usedFor": "Barrel nut, castle nut, muzzle device" }, { "tool": "Pivot pin detent installation tool (or 3/32\" punch)", "usedFor": "Holding the pivot pin detent while the pin goes in" }, { "tool": "Roll-pin starter punches (1/16\", 3/32\", 1/8\") and a bench block", "usedFor": "Bolt catch, trigger guard, forward assist and ejection port cover pins" }, { "tool": "Lower receiver vise block", "usedFor": "Supporting the trigger guard ears and bolt catch boss" } ], "fitOnRebuild": [ { "check": "Barrel nut torque and gas tube alignment", "why": "The barrel nut is torqued within a range and indexed for the gas tube", "source": { "title": "TM 9-1005-249-23&P, Rifle, 5.56mm, M16 and M16A1 (unit and direct support, incl. RPSTL)", "publisher": "Department of the Army", "reliability": "primary", "url": "https://archive.org/download/ArmyTechnicalManualforM16Rifle-Tm9-1005-249-23p/Manual-Tm9-1005-249-23p_djvu.txt", "page": null, "pdfPage": null, "pageUrl": null, "quote": "torque barrel nut assembly (8) to 30 ft-lb." } }, { "check": "DD rail torque", "why": "DD publishes rail removal/installation torque values on request", "source": { "title": "Daniel Defense DD4 / DDM4 / DD5 Rifle Manual (2016, Rev 3.1)", "publisher": "Daniel Defense", "reliability": "primary", "url": "https://308ar.com/wp-content/uploads/2017/03/Daniel-Defense-DD4-DD5-Rifle-Manual.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "Removal/installation instructions and torque specifications are available from Daniel Defense." } }, { "check": "Headspace if the barrel or bolt is changed", "why": "Bolt-to-barrel headspace is set by the factory; mixing bolts and barrels needs a gauge check", "source": null }, { "check": "Gas key staking and screw torque", "why": "If the carrier key is disturbed the screws are torqued and staked", "source": { "title": "TM 9-1005-249-23&P, Rifle, 5.56mm, M16 and M16A1 (unit and direct support, incl. RPSTL)", "publisher": "Department of the Army", "reliability": "primary", "url": "https://archive.org/download/ArmyTechnicalManualforM16Rifle-Tm9-1005-249-23p/Manual-Tm9-1005-249-23p_djvu.txt", "page": null, "pdfPage": null, "pageUrl": null, "quote": "torque the carrier and key screws (3) to 35 to" } }, { "check": "Function check (safety, hammer reset, disconnector)", "why": "The hammer spring orientation and disconnector seating are checked with a function check", "source": null }, { "check": "Sight/optic re-zero", "why": "The front sight base, rail or optic moves when the barrel/handguard comes off", "source": null } ], "assessed": "2026-10-29" }, "videos": [], "configurations": [], "tools": [], "phases": [ { "id": "clear", "title": "Clear and make safe", "steps": [ { "n": 1, "instruction": "Point the muzzle in a safe direction and keep your finger off the trigger." }, { "n": 2, "instruction": "Press the magazine release and remove the magazine.", "partsFreed": [ "Magazine" ] }, { "n": 3, "instruction": "Pull the charging handle fully to the rear and lock the bolt back with the bolt catch." }, { "n": 4, "instruction": "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." }, { "n": 5, "instruction": "If the hammer is cocked, place the selector on SAFE." }, { "n": 6, "instruction": "Remove all live ammunition from the work area." } ], "videos": [] }, { "id": "disassemble", "title": "Disassemble", "videos": [], "procedures": [ { "procedure": "field-strip", "title": "Field Strip", "level": "field-strip", "configuration": false, "steps": [ { "n": 1, "instruction": "Complete the Clear and Make Safe procedure and release the bolt forward." }, { "n": 2, "instruction": "Push the rear takedown pin from the left side until it stops in its captured position.", "tip": "If tight, tap it with a punch or a case rim rather than levering it." }, { "n": 3, "instruction": "Pivot the upper receiver forward on the front pivot pin." }, { "n": 4, "instruction": "Push the front pivot pin out to its captured position and separate the upper from the lower receiver.", "partsFreed": [ "Upper receiver assembly" ] }, { "n": 5, "instruction": "Pull the charging handle partway rearward and withdraw the bolt carrier group.", "partsFreed": [ "Bolt carrier group" ] }, { "n": 6, "instruction": "Pull the charging handle down and out of its channel.", "warning": "The charging handle comes out after the carrier, never before.", "partsFreed": [ "Charging handle" ] } ] } ] }, { "id": "refinish", "title": "Refinish", "components": [ { "name": "Upper receiver assembly", "procedure": "field-strip", "level": "field-strip", "step": 4 }, { "name": "Bolt carrier group", "procedure": "field-strip", "level": "field-strip", "step": 5 }, { "name": "Charging handle", "procedure": "field-strip", "level": "field-strip", "step": 6 } ], "manufacturerPartsList": null, "partsDiagrams": [], "materials": [], "note": "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." }, { "id": "reassemble", "title": "Reassemble", "videos": [], "procedures": [ { "procedure": "reassembly", "title": "Reassembly", "configuration": false, "steps": [ { "n": 1, "instruction": "Insert the bolt into the carrier with the extractor oriented toward the ejection port side." }, { "n": 2, "instruction": "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." }, { "n": 3, "instruction": "Drop the firing pin into the rear of the carrier, tail first, and let it seat fully." }, { "n": 4, "instruction": "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." }, { "n": 5, "instruction": "Insert the charging handle into its channel and push it partway forward." }, { "n": 6, "instruction": "Insert the bolt carrier group into the charging handle’s track and slide both fully home." }, { "n": 7, "instruction": "Mate the upper to the lower, press the front pivot pin home, close the receivers, and press the rear takedown pin home." }, { "n": 8, "instruction": "Charge the rifle and perform the function check." } ], "instruction": null } ] }, { "id": "torque", "title": "Torque", "coverage": "sourced", "manufacturer": [ { "fastener": "Barrel nut (DD RIS II Bolt-Up System barrel nut)", "appliesTo": "Daniel Defense RIS II rail, models M4A1, M4A1 FSP and MK18 (the rail used on DD's M4A1/MK18-configuration rifles)", "qualifier": "exact", "value": 55, "valueMax": null, "unit": "ft-lb", "converted": { "value": { "N-m": 74.6, "in-lb": 660, "ft-lb": 55 }, "valueMax": null }, "sequence": "Slide the barrel nut over the barrel and thread onto the upper receiver hand-tight, then torque with the Daniel Defense barrel nut wrench. The Bolt-Up Plate will remain loose. Reinstall low-profile gas block and gas tube.", "threadlocker": null, "source": { "title": "RIS II Rail Interface System II Installation Instructions (RIS II models M4A1, M4A1 FSP, MK18)", "publisher": "Daniel Defense (document re-hosted by ManualShelf; original at danieldefense.com/media/asset/r/i/ris_ii_instructions.pdf, which was blocked from this environment)", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ris-ii-rail/installation-instructions-english/page-2.html", "page": "2", "pdfPage": null, "pageUrl": null, "quote": "Tighten the barrel nut to 55 ft/lbs using the Daniel Defense barrel nut wrench." } }, { "fastener": "RIS II rail screws (six, 7/8\") through the Bolt-Up Plate", "appliesTo": "Daniel Defense RIS II rail, models M4A1, M4A1 FSP and MK18", "qualifier": "range", "value": 29, "valueMax": 32, "unit": "in-lb", "converted": { "value": { "N-m": 3.3, "in-lb": 29, "ft-lb": 2.4 }, "valueMax": { "N-m": 3.6, "in-lb": 32, "ft-lb": 2.7 } }, "sequence": "Tighten all six screws in the following pattern: the center screws first, the bottom screws next, and the top screws last. Reinstall muzzle device.", "threadlocker": null, "source": { "title": "RIS II Rail Interface System II Installation Instructions (RIS II models M4A1, M4A1 FSP, MK18)", "publisher": "Daniel Defense (document re-hosted by ManualShelf)", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ris-ii-rail/installation-instructions-english.html", "page": "PDF p. 1 (ManualShelf text view)", "pdfPage": null, "pageUrl": null, "quote": "Insert the four remaining 7/8\" screws from the receiver toward the muzzle through the Bolt-Up Plate into the RIS II, and tighten all six screws to 29-32 in/lbs using the supplied allen wrench in the following pattern: the center screws first, the bottom screws next, and the top screws last." } }, { "fastener": "Integral suppressor baffle (left-hand thread)", "appliesTo": "DDM4 ISR (integrally suppressed barrel)", "qualifier": "range", "value": 20, "valueMax": 25, "unit": "ft-lb", "converted": { "value": { "N-m": 27.1, "in-lb": 240, "ft-lb": 20 }, "valueMax": { "N-m": 33.9, "in-lb": 300, "ft-lb": 25 } }, "sequence": "Support the barrel extension lugs in an upper receiver bench block in a vise; use a torque-limiting (preferred) 1/2\" square-drive wrench and the provided tool; threads are left-handed. Lightly oil the threads before re-installing. 'WARNING: DO NOT OVER TIGHTEN PAST 25 LB-FT. THIS MAY DAMAGE THE SUPPRESSOR ASSEMBLY AND RESULT IN THE PROJECTILE STRIKING THE BAFFLE UPON FIRING.'", "threadlocker": null, "source": { "title": "Daniel Defense DDM4 Safety & Maintenance Instructions (German/English)", "publisher": "Daniel Defense (manual re-hosted by ManualShelf)", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ddm4/safety-maintenance-instructions-german-english/page-36.html", "page": "ManualShelf page 36", "pdfPage": null, "pageUrl": null, "quote": "Re-install the bafe per the instructions provided in the manual, remembering that the threads are left-handed. Torque the bafe to 20-25 lb-ft." } } ], "reported": [ { "fastener": "Rail screws (4) through the Bolt-Up Collar", "appliesTo": "DDM4 (e.g. V7 with MFR XL 15.0) — Daniel Defense MFR / MFR XL (M-LOK or KeyMod) and MFR XS rails", "qualifier": "range", "value": 25, "valueMax": 28, "unit": "in-lb", "converted": { "value": { "N-m": 2.8, "in-lb": 25, "ft-lb": 2.1 }, "valueMax": { "N-m": 3.2, "in-lb": 28, "ft-lb": 2.3 } }, "sequence": "Insert all four screws from the receiver toward the muzzle; tighten in an alternating pattern; without a wrench, a quarter to half turn past first resistance.", "threadlocker": null, "source": { "title": "Daniel Defense MFR / MFR XL Rail (M-LOK) — Installation Instructions, Rev 1.0 (served from www.danieldefense.com; the bare danieldefense.com host returns 403)", "publisher": "Daniel Defense, Inc.", "reliability": "secondary", "url": "https://www.danieldefense.com/media/asset/m/f/mfr_mfrxl_rail_m-lok_instructions.pdf", "page": "PDF p. 1, step 5", "pdfPage": 1, "pageUrl": "https://www.danieldefense.com/media/asset/m/f/mfr_mfrxl_rail_m-lok_instructions.pdf#page=1", "quote": "If you have an inch/pound torque wrench, the torque specification is 25-28 in/lbs." } }, { "fastener": "Barrel nut (Daniel Defense Bolt-Up System barrel nut, MFR XS)", "appliesTo": "DDM4 / AR-15 upper fitted with a Daniel Defense MFR XS rail", "qualifier": "exact", "value": 50, "valueMax": null, "unit": "ft-lb", "converted": { "value": { "N-m": 67.8, "in-lb": 600, "ft-lb": 50 }, "valueMax": null }, "sequence": "The Bolt-Up Plate remains loose after the nut is torqued.", "threadlocker": null, "source": { "title": "Daniel Defense MFR XS Rail — Installation Instructions (served from www.danieldefense.com)", "publisher": "Daniel Defense, Inc.", "reliability": "secondary", "url": "https://www.danieldefense.com/media/asset/m/f/mfr_xs_rail_installation_instructions.pdf", "page": "PDF p. 1, step 2", "pdfPage": 1, "pageUrl": "https://www.danieldefense.com/media/asset/m/f/mfr_xs_rail_installation_instructions.pdf#page=1", "quote": "Tighten the Bolt-Up System Barrel Nut and torque to 50 ft/lbs using the supplied Daniel Defense Bolt-Up System Barrel Nut Wrench." } }, { "fastener": "Rail screws (4) through the Bolt-Up Plate", "appliesTo": "DDM4 fitted with a Daniel Defense DDM4 Rail or SLiM Rail", "qualifier": "exact", "value": 32, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 3.6, "in-lb": 32, "ft-lb": 2.7 }, "valueMax": null }, "sequence": "Tighten all four screws in an alternating pattern; without a wrench, a quarter to half turn past first resistance.", "threadlocker": null, "source": { "title": "Daniel Defense DDM4 Rail — Installation Instructions, Rev 1.0 (served from www.danieldefense.com)", "publisher": "Daniel Defense, Inc.", "reliability": "secondary", "url": "https://www.danieldefense.com/media/asset/d/d/ddm4_rail_instructions.pdf", "page": "PDF p. 1, step 4", "pdfPage": 1, "pageUrl": "https://www.danieldefense.com/media/asset/d/d/ddm4_rail_instructions.pdf#page=1", "quote": "If you have an inch/pound torque wrench, the torque specification is 32 in/lbs." } } ], "notes": null }, { "id": "function-check", "title": "Function check", "checks": [ "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." ], "videos": [] } ], "troubleshooting": [], "sources": [ { "n": 1, "id": null, "title": "TM 9-1005-319-10: Rifle, 5.56mm, M16A2/M4 Carbine", "publisher": "U.S. Department of the Army", "reliability": "primary", "url": null, "accessed": null }, { "n": 2, "id": null, "title": "Daniel Defense DDM4 Owner’s Manual", "publisher": "Daniel Defense", "reliability": "primary", "url": null, "accessed": null }, { "n": 3, "id": "daniel-defense-document-re-hosted-by-92bb3b", "title": "RIS II Rail Interface System II Installation Instructions (RIS II models M4A1, M4A1 FSP, MK18)", "publisher": "Daniel Defense (document re-hosted by ManualShelf; original at danieldefense.com/media/asset/r/i/ris_ii_instructions.pdf, which was blocked from this environment)", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ris-ii-rail/installation-instructions-english/page-2.html", "accessed": "2026-09-27" }, { "n": 4, "id": "daniel-defense-document-re-hosted-by-564847", "title": "RIS II Rail Interface System II Installation Instructions (RIS II models M4A1, M4A1 FSP, MK18)", "publisher": "Daniel Defense (document re-hosted by ManualShelf)", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ris-ii-rail/installation-instructions-english.html", "accessed": "2026-09-27" }, { "n": 5, "id": "daniel-defense-manual-re-hosted-by-m-c8ab4b", "title": "Daniel Defense DDM4 Safety & Maintenance Instructions (German/English)", "publisher": "Daniel Defense (manual re-hosted by ManualShelf)", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ddm4/safety-maintenance-instructions-german-english/page-36.html", "accessed": "2026-09-27" }, { "n": 6, "id": "daniel-defense-stance-256efe", "title": "Daniel Defense DDM4 / DD5 Safety & Maintenance Instructions (German/English), section 5.1 Stripping for Cleaning (Daniel Defense manual, copy hosted by ManualShelf)", "publisher": "Daniel Defense", "reliability": "primary", "url": "https://www.manualshelf.com/manual/daniel-defense/ddm4/safety-maintenance-instructions-german-english/page-30.html", "accessed": "2026-10-11" }, { "n": 7, "id": "daniel-defense-inc-4a6049", "title": "Daniel Defense MFR / MFR XL Rail (M-LOK) — Installation Instructions, Rev 1.0 (served from www.danieldefense.com; the bare danieldefense.com host returns 403)", "publisher": "Daniel Defense, Inc.", "reliability": "secondary", "url": "https://www.danieldefense.com/media/asset/m/f/mfr_mfrxl_rail_m-lok_instructions.pdf", "accessed": "2026-10-11" }, { "n": 8, "id": "daniel-defense-inc-3512cf", "title": "Daniel Defense MFR XS Rail — Installation Instructions (served from www.danieldefense.com)", "publisher": "Daniel Defense, Inc.", "reliability": "secondary", "url": "https://www.danieldefense.com/media/asset/m/f/mfr_xs_rail_installation_instructions.pdf", "accessed": "2026-10-11" }, { "n": 9, "id": "daniel-defense-inc-da6575", "title": "Daniel Defense DDM4 Rail — Installation Instructions, Rev 1.0 (served from www.danieldefense.com)", "publisher": "Daniel Defense, Inc.", "reliability": "secondary", "url": "https://www.danieldefense.com/media/asset/d/d/ddm4_rail_instructions.pdf", "accessed": "2026-10-11" }, { "n": 10, "id": "tier-33655209", "title": "Daniel Defense DD4 / DDM4 / DD5 Rifle Manual (2016, Rev 3.1)", "publisher": "Daniel Defense", "reliability": "primary", "url": "https://308ar.com/wp-content/uploads/2017/03/Daniel-Defense-DD4-DD5-Rifle-Manual.pdf", "accessed": "2026-10-29" }, { "n": 11, "id": "tier-69c2cd81", "title": "AR Lower Receiver Build: Pivot Pin Installation", "publisher": "Shooting Illustrated (NRA)", "reliability": "secondary", "url": "https://www.shootingillustrated.com/content/ar-lower-receiver-build-pivot-pin-installation/", "accessed": "2026-10-29" }, { "n": 12, "id": "tier-616a4c9f", "title": "TM 9-1005-249-23&P, Rifle, 5.56mm, M16 and M16A1 (unit and direct support, incl. RPSTL)", "publisher": "Department of the Army", "reliability": "primary", "url": "https://archive.org/download/ArmyTechnicalManualforM16Rifle-Tm9-1005-249-23p/Manual-Tm9-1005-249-23p_djvu.txt", "accessed": "2026-10-29" }, { "n": 13, "id": "tier-c7d46d0f", "title": "TFB Armorer's Bench: Complete AR15 Assembly - Lower Receiver", "publisher": "The Firearm Blog", "reliability": "secondary", "url": "https://www.thefirearmblog.com/blog/2022/07/31/tfb-armorers-bench-complete-ar15-assembly-lower-receiver/", "accessed": "2026-10-29" } ] }