{ "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": "fn-scar-17", "name": "FN SCAR 17S", "manufacturer": { "id": "fn-herstal", "name": "FN Herstal" }, "category": "rifle", "action": "gas-operated-short-stroke", "calibers": [ "7.62x51mm NATO", ".308 Winchester", "5.56x45mm NATO" ], "alsoKnownAs": [ "SCAR-H", "Mk 17", "SCAR 16S (5.56 version)" ], "coversAlso": [ "FN SCAR 16S in 5.56mm", "Mk 16 and Mk 17 military variants" ], "page": "firearms/fn-scar-17.html", "bundle": "api/v1/firearms/fn-scar-17.json", "lastUpdated": "2026-10-29" }, "notices": [ "FN Herstal limits owner disassembly: Trigger module, buttstock module, moving parts (bolt carrier, charging sled, bolt removed from carrier), gas regulator and piston. Do not disassemble the bolt, the buffer or the charging sled further.", "This work order is written for the FN SCAR 17S. It is reported to cover FN SCAR 16S in 5.56mm; Mk 16 and Mk 17 military variants — if the firearm on the bench is one of those, check the torque notes: values do not always carry over." ], "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": "medium", "verification": "community-reviewed" }, "manufacturerDisassembly": { "status": "limited", "limit": "Trigger module, buttstock module, moving parts (bolt carrier, charging sled, bolt removed from carrier), gas regulator and piston. Do not disassemble the bolt, the buffer or the charging sled further.", "statement": "FN tells owners not to take the action apart beyond the manual's procedure (no bolt or buffer disassembly) and to contact the FN Service Center if further disassembly is needed.", "source": { "title": "FN SCAR 16S/17S/20S Owner's Manual (2512)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf", "page": "42", "pdfPage": 44, "pageUrl": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf#page=44", "quote": "DO NOT TAKE YOUR FIREARM’S ACTION APART BEYOND WHAT IS EXPLAINED IN THIS OWNER’S MANUAL. THIS IS A SPECIALIZED, FINELY FITTED MECHANISM; ANY ATTEMPT TO DISASSEMBLE THE INNER MECHANISM MAY DAMAGE IT FOR LIFE." } }, "recalls": [], "shopTier": { "tier": 2, "group": "rifle", "rating": "Pew-Takedown editorial rating (1 easy – 3 hardest), not the manufacturer's", "reason": "The upper is a monolithic receiver; the barrel comes out on six captive Torx screws torqued in sequence, and the trigger module, bolt carrier and stock come off with finger pressure. FN treats the trigger module and other inner assemblies as factory-only, and a barrel removal means a headspace check. There are few parts to handle, but the torque spec, headspace gauging and a sealed trigger module make it moderate.", "confidence": "medium", "partCount": null, "painPoints": [ { "issue": "FN says the inner mechanism assemblies (trigger module internals, bolt) are finely fitted and go back to FN for anything past the field strip.", "during": "both", "source": { "title": "Autoloading Rifle Owner's Manual FN SCAR 16S and 17S (2016)", "publisher": "FN America", "reliability": "primary", "url": "https://s3.amazonaws.com/files.ammunitiondepot.com/fn-firearms/carbines-discontinued/fn-scar-16s-17s-owners-manual-2016.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "YOU MAY DAMAGE IT BEYOND REPAIR OR LOSE SMALL PARTS BY ATTEMPTING TO DISASSEMBLE THE INNER MECHANISM ASSEMBLIES." } }, { "issue": "The six barrel screws are captive: they are backed to the end of travel but not removed, then torqued back in a rear-to-front alternating sequence at 62 in-lb; a ft-lb wrench strips them.", "during": "both", "source": { "title": "Instructions for FN SCAR 16S and 17S Barrel Change (63903, 2303)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "Using the torque wrench set at 62 inch-pounds (7Nm) and a TORX T-25 adapter, tighten the barrel screws starting at the rear of the barrel extension (alternating sides)" } }, { "issue": "Any barrel off/on needs a GO/NO-GO headspace check by an armorer.", "during": "reassembly", "source": { "title": "Instructions for FN SCAR 16S and 17S Barrel Change (63903, 2303)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "the headspace must be checked by a certified armorer or gunsmith using a set of GO/NO-GO headspace gages" } } ], "minutes": { "strip": 40, "rebuild": 60, "basis": "estimated", "note": "Estimate: field strip (trigger module, return spring, bolt carrier, charging handle), barrel out on six screws, front/rear sights, muzzle device, stock and hinge, lower; trigger module not stripped. Rebuild longer for the barrel screw torque sequence, headspace check and function check.", "source": null }, "stripScope": [ { "assembly": "Upper receiver", "removes": [ "barrel assembly (6 captive T-25 screws)", "charging handle", "bolt carrier and bolt (firing pin, cam pin, extractor)", "return spring assembly", "front and rear folding sights", "flash hider" ], "tools": [ "T-25 Torx, in-lb torque wrench", "headspace gauges" ] }, { "assembly": "Lower / trigger module", "removes": [ "trigger module (removed as a unit, not stripped)", "lower receiver" ] }, { "assembly": "Stock", "removes": [ "folding stock assembly and hinge", "cheek piece", "butt plate" ] } ], "hardware": null, "specialTools": [ { "tool": "Inch-pound torque wrench with T-25 Torx bit", "usedFor": "Barrel screws, 62 in-lb (7 N·m)" }, { "tool": "GO/NO-GO headspace gauges (7.62x51)", "usedFor": "After the barrel is refitted" }, { "tool": "M16/AR15 A2 front sight tool", "usedFor": "Front sight post" }, { "tool": "Muzzle device wrench", "usedFor": "Flash hider" } ], "fitOnRebuild": [ { "check": "Barrel screw torque and sequence", "why": "Rear-to-front, alternating, 62 in-lb", "source": { "title": "Instructions for FN SCAR 16S and 17S Barrel Change (63903, 2303)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "Using the torque wrench set at 62 inch-pounds (7Nm) and a TORX T-25 adapter, tighten the barrel screws starting at the rear of the barrel extension (alternating sides)" } }, { "check": "Headspace", "why": "Bolt/barrel combination must be gauged after a barrel change", "source": { "title": "Instructions for FN SCAR 16S and 17S Barrel Change (63903, 2303)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf", "page": null, "pdfPage": null, "pageUrl": null, "quote": "the headspace must be checked by a certified armorer or gunsmith using a set of GO/NO-GO headspace gages" } }, { "check": "Zero", "why": "The barrel moves relative to the top rail and optics; re-zero", "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": "Place the selector on safe." }, { "n": 3, "instruction": "Press the magazine release and remove the magazine.", "partsFreed": [ "Magazine" ] }, { "n": 4, "instruction": "Pull the charging handle fully to the rear and lock the bolt back if the rifle has a hold-open." }, { "n": 5, "instruction": "Inspect the chamber and magazine well with a light, then physically confirm the chamber is empty.", "warning": "Look and feel. Both, every time." }, { "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 out the two receiver takedown pins.", "partsFreed": [ "Takedown pins" ] }, { "n": 3, "instruction": "Separate the upper receiver from the lower receiver.", "partsFreed": [ "Upper receiver assembly" ] }, { "n": 4, "instruction": "Withdraw the bolt carrier group and its recoil spring guide rods rearward out of the upper receiver.", "warning": "The recoil springs are under compression.", "partsFreed": [ "Bolt carrier group", "Recoil spring assembly" ] }, { "n": 5, "instruction": "Remove the firing pin retaining pin, withdraw the firing pin, rotate and lift the cam pin, and withdraw the bolt.", "partsFreed": [ "Firing pin", "Cam pin", "Bolt" ] }, { "n": 6, "instruction": "Rotate and withdraw the gas piston and its components from the gas block, noting orientation.", "partsFreed": [ "Gas piston" ] } ] } ] }, { "id": "refinish", "title": "Refinish", "components": [ { "name": "Takedown pins", "procedure": "field-strip", "level": "field-strip", "step": 2 }, { "name": "Upper receiver assembly", "procedure": "field-strip", "level": "field-strip", "step": 3 }, { "name": "Bolt carrier group", "procedure": "field-strip", "level": "field-strip", "step": 4 }, { "name": "Recoil spring assembly", "procedure": "field-strip", "level": "field-strip", "step": 4 }, { "name": "Firing pin", "procedure": "field-strip", "level": "field-strip", "step": 5 }, { "name": "Cam pin", "procedure": "field-strip", "level": "field-strip", "step": 5 }, { "name": "Bolt", "procedure": "field-strip", "level": "field-strip", "step": 5 }, { "name": "Gas piston", "procedure": "field-strip", "level": "field-strip", "step": 6 } ], "manufacturerPartsList": null, "partsDiagrams": [], "materials": [ { "component": "Receiver (upper)", "material": "aluminum", "finish": "Hard-anodized", "appliesTo": "FN SCAR 17S NRCH, 16.25in (page lists BLK, FDE and GRY colour SKUs)", "note": null, "source": { "title": "FN SCAR® 17S NRCH — product page (Specs / Primary Features)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/products/rifles/fn-scar-17s-nrch/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "RECEIVER … Hard-anodized monolithic aluminum" } }, { "component": "Barrel", "material": null, "finish": "chrome-lined", "appliesTo": "FN SCAR 17S NRCH, 16.25in (page lists BLK, FDE and GRY colour SKUs)", "note": null, "source": { "title": "FN SCAR® 17S NRCH — product page (Specs / Primary Features)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/products/rifles/fn-scar-17s-nrch/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "BARREL … Cold hammer-forged, chrome-lined, fully free-floating with compensator" } }, { "component": "Stock", "material": "polymer", "finish": null, "appliesTo": "FN SCAR 17S NRCH, 16.25in (page lists BLK, FDE and GRY colour SKUs)", "note": null, "source": { "title": "FN SCAR® 17S NRCH — product page (Specs / Primary Features)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/products/rifles/fn-scar-17s-nrch/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "STOCK … Telescoping side-folding polymer stock" } }, { "component": "Magazine", "material": "Steel", "finish": null, "appliesTo": "FN SCAR 17S NRCH, 16.25in (page lists BLK, FDE and GRY colour SKUs)", "note": null, "source": { "title": "FN SCAR® 17S NRCH — product page (Specs / Primary Features)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/products/rifles/fn-scar-17s-nrch/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "MAGAZINE … Steel body" } } ], "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": "Reinstall the gas piston and its components in the correct orientation." }, { "n": 2, "instruction": "Fit the bolt into the carrier, install and rotate the cam pin, then the firing pin and retaining pin." }, { "n": 3, "instruction": "Insert the bolt carrier group and guide rods into the upper receiver and seat them." }, { "n": 4, "instruction": "Mate the upper to the lower and press both takedown pins fully home." }, { "n": 5, "instruction": "Cycle the action several times and perform the function check." } ], "instruction": null } ] }, { "id": "torque", "title": "Torque", "coverage": "sourced", "manufacturer": [ { "fastener": "Barrel screws: four rear barrel extension screws and two forward barrel support screws (captive, TORX T-25)", "appliesTo": "FN SCAR 16S and 17S", "qualifier": "exact", "value": 62, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 7, "in-lb": 62, "ft-lb": 5.2 }, "valueMax": null }, "sequence": "Seat the barrel extension lugs in the receiver cutaway, slide rearward until all barrel extension screws align, guide the front barrel support into the receiver; tighten the barrel screws starting at the rear of the barrel extension (alternating sides) and moving forward, per the 1-6 sequence in Figure 11, applying downward pressure.", "threadlocker": null, "source": { "title": "Instructions for FN SCAR 16S and 17S Barrel Change (63903, 2303)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf", "page": "PDF p. 2 (Barrel Assembly Installation, ", "pdfPage": 2, "pageUrl": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf#page=2", "quote": "Using the torque wrench set at 62 inch-pounds (7Nm) and a TORX T-25 adapter, tighten the barrel screws starting at the rear of the barrel extension (alternating sides) and moving forward on the rifle (Figure 11)." } }, { "fastener": "Barrel extension screws (TORX T-25), refitting the barrel after NRCH conversion", "appliesTo": "FN SCAR 16S/17S (NRCH kit P/N 20-100505 for 17S/20S)", "qualifier": "exact", "value": 62, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 7, "in-lb": 62, "ft-lb": 5.2 }, "valueMax": null }, "sequence": "Starting from the rear, in the order of Figure 18 (1-6), applying downward pressure and turning clockwise.", "threadlocker": null, "source": { "title": "Instructions for FN SCAR Non-Reciprocating Charging Handle Kit (FN002 R3)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/02/FN002-SCAR-NRCH-Instruction-Manual-R3-05-20-2269.pdf", "page": "PDF p. 12", "pdfPage": 12, "pageUrl": "https://fnamerica.com/wp-content/uploads/2024/02/FN002-SCAR-NRCH-Instruction-Manual-R3-05-20-2269.pdf#page=12", "quote": "Using the torque wrench set at 62 inch-pounds (7Nm) and a TORX® T-25 adapter, starting from the rear, tighten the barrel extension screws in the order outlined in Figure 18." } }, { "fastener": "NRCH front plate screws (2.5 mm hex)", "appliesTo": "FN SCAR 16S/17S converted with FN's NRCH kit (P/N 20-100505 for 17S/20S)", "qualifier": "exact", "value": 22.1, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 2.5, "in-lb": 22.1, "ft-lb": 1.8 }, "valueMax": null }, "sequence": null, "threadlocker": "Loctite 263 permanent high strength thread locker (or equivalent); allow 24 hours cure", "source": { "title": "Instructions for FN SCAR Non-Reciprocating Charging Handle Kit (FN002 R3)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/02/FN002-SCAR-NRCH-Instruction-Manual-R3-05-20-2269.pdf", "page": "PDF p. 10", "pdfPage": 10, "pageUrl": "https://fnamerica.com/wp-content/uploads/2024/02/FN002-SCAR-NRCH-Instruction-Manual-R3-05-20-2269.pdf#page=10", "quote": "Use a torque wrench set at 22.1 in/lbs (2.5Nm) with a 2.5mm hex bit to tighten the two front plate screws." } }, { "fastener": "SCAR-SC receiver rear plate screws (four 2.5 mm side screws, one 3 mm top screw)", "appliesTo": "FN SCAR 16S/17S/20S fitted with FN's SCAR-SC rear stock (\"installation procedures for SCAR 16S, SCAR 17S and SCAR 20S are identical\")", "qualifier": "exact", "value": 22.1, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 2.5, "in-lb": 22.1, "ft-lb": 1.8 }, "valueMax": null }, "sequence": null, "threadlocker": "Loctite 263 permanent high strength thread locker (or equivalent); allow 24 hours cure", "source": { "title": "Instructions for FN SCAR-SC Rear Stock (2407)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2025/02/2407_FNSCAR-SC-Stock-Install.pdf", "page": "PDF p. 2", "pdfPage": 2, "pageUrl": "https://fnamerica.com/wp-content/uploads/2025/02/2407_FNSCAR-SC-Stock-Install.pdf#page=2", "quote": "Use a torque wrench set at 22.1 in/lbs (2.5Nm) with a 2.5mm hex bit to tighten the four side screws and a 3mm hex bit for the top screw." } }, { "fastener": "M-LOK QD sling mount screws (5/32\" hex)", "appliesTo": "FN SCAR 16S, 17S, 20S", "qualifier": "maximum", "value": 35, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 4, "in-lb": 35, "ft-lb": 2.9 }, "valueMax": null }, "sequence": null, "threadlocker": null, "source": { "title": "FN SCAR 16S/17S/20S Owner's Manual (2512)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf", "page": "PDF p. 57 (M-LOK QD sling mount)", "pdfPage": 57, "pageUrl": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf#page=57", "quote": "Secure the M-LOK screws using a 5/32” hex wrench (Do not exceed 35 in/lbs.)." } }, { "fastener": "M-LOK vertical foregrip screws (5/32\" hex)", "appliesTo": "FN SCAR 16S and 17S", "qualifier": "maximum", "value": 15, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 1.7, "in-lb": 15, "ft-lb": 1.2 }, "valueMax": null }, "sequence": null, "threadlocker": null, "source": { "title": "FN SCAR 16S/17S/20S Owner's Manual (2512)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf", "page": "PDF p. 58 (22.4 Vertical foregrip)", "pdfPage": 58, "pageUrl": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf#page=58", "quote": "Secure the M-LOK screws using a 5/32” hex wrench (Do not exceed 15 in/lbs.)." } } ], "reported": [ { "fastener": "Rear barrel extension screws (4, T-25 Torx)", "appliesTo": "FN SCAR 16 and 17 (instructions for fitting the Midwest Industries MI-S1617 extension rail, which reuses the factory screws)", "qualifier": "exact", "value": 62, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 7, "in-lb": 62, "ft-lb": 5.2 }, "valueMax": null }, "sequence": "Start the forward barrel screws (do not tighten), slide the barrel rearward and start the 4 rear barrel extension screws (do not tighten), fit the rail, then tighten the four rear barrel extension screws in an alternating pattern; then the six remaining T-25 screws in the rail and front trunnion to 45 in/lbs. 'DO NOT attempt to remove the receiver assembly screws, located in the middle of each block.'", "threadlocker": null, "source": { "title": "MI-S1617 FNH SCAR 16, 17 Extension Rail Installation Instructions", "publisher": "Midwest Industries, Inc.", "reliability": "secondary", "url": "https://midwestindustriesinc.com/content/installation-instructions/SCAR-Extension-Rail-MI-S1617-Instructions.pdf", "page": "PDF p. 1", "pdfPage": 1, "pageUrl": "https://midwestindustriesinc.com/content/installation-instructions/SCAR-Extension-Rail-MI-S1617-Instructions.pdf#page=1", "quote": "Tighten the four rear barrel extension screws in an alternating pattern to 62 in/lbs. of torque." } }, { "fastener": "Barrel screws (factory four T25 screws)", "appliesTo": "FN SCAR (barrel assembly to upper receiver; KDG MREX MkII rail instructions)", "qualifier": "exact", "value": 62, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 7, "in-lb": 62, "ft-lb": 5.2 }, "valueMax": null }, "sequence": "Slide the barrel (with rail) assembly into the upper receiver and tighten the factory four T25 screws in a crisscross pattern.", "threadlocker": null, "source": { "title": "MREX MkII Installation Instructions", "publisher": "Kinetic Development Group (KDG)", "reliability": "secondary", "url": "https://kineticdg.com/instruction/mrex-mkii-installation-instructions/", "page": null, "pdfPage": null, "pageUrl": null, "quote": "FNH recommends tightening the barrel to the factory installed 62 in/lbs in a crisscross pattern." } }, { "fastener": "Rail and front trunnion screws (6, T-25), with MI extension rail fitted", "appliesTo": "FN SCAR 16/17 fitted with Midwest Industries MI-S1617 extension rail", "qualifier": "exact", "value": 45, "valueMax": null, "unit": "in-lb", "converted": { "value": { "N-m": 5.1, "in-lb": 45, "ft-lb": 3.7 }, "valueMax": null }, "sequence": null, "threadlocker": null, "source": { "title": "MI-S1617 FNH SCAR 16, 17 Extension Rail Installation Instructions", "publisher": "Midwest Industries, Inc.", "reliability": "secondary", "url": "https://midwestindustriesinc.com/content/installation-instructions/SCAR-Extension-Rail-MI-S1617-Instructions.pdf", "page": "PDF p. 1", "pdfPage": 1, "pageUrl": "https://midwestindustriesinc.com/content/installation-instructions/SCAR-Extension-Rail-MI-S1617-Instructions.pdf#page=1", "quote": "Tighten the six remaining T-25 screws in the rail and front trunion to 45in/lbs." } } ], "notes": "The manufacturer's documents give no torque value. They say: \"Reinsert the safety selector lever screw into the larger hole of the safety selector lever and hand-tighten with a 5/64” flathead screwdriver until the screw is flush with the safety selector lever body (Figure 69). Do not over tighten.\" (FN SCAR 16S/17S/20S Owner's Manual (2512), PDF p. 55) \"Install the rear sight assembly to the receiver top rail using a T25 wrench. Use only enough torque to snug the clamping screw.\" (Instructions for FN SCAR-SC Rear Stock (2407), PDF p. 2)" }, { "id": "function-check", "title": "Function check", "checks": [ "Verify the rifle is unloaded with no magazine inserted before each step.", "Cycle the action by hand and confirm the bolt locks and returns fully to battery.", "With the selector on safe, press the trigger. The hammer must not fall.", "Move the selector to fire, cycle the action, and press the trigger. The hammer should fall.", "Hold the trigger back, cycle the action, and release slowly to feel the disconnector reset.", "Confirm the magazine seats and locks positively and any hold-open engages on an empty magazine.", "Confirm the folding stock locks positively in the extended position.", "Confirm the gas regulator is on the correct setting." ], "videos": [] } ], "troubleshooting": [], "sources": [ { "n": 1, "id": null, "title": "FN SCAR 17S Operator’s Manual", "publisher": "FN America", "reliability": "primary", "url": null, "accessed": null }, { "n": 2, "id": "midwest-industries-inc-0ec8ae", "title": "MI-S1617 FNH SCAR 16, 17 Extension Rail Installation Instructions", "publisher": "Midwest Industries, Inc.", "reliability": "secondary", "url": "https://midwestindustriesinc.com/content/installation-instructions/SCAR-Extension-Rail-MI-S1617-Instructions.pdf", "accessed": "2026-09-27" }, { "n": 3, "id": "kinetic-development-group-kdg-f5b951", "title": "MREX MkII Installation Instructions", "publisher": "Kinetic Development Group (KDG)", "reliability": "secondary", "url": "https://kineticdg.com/instruction/mrex-mkii-installation-instructions/", "accessed": "2026-09-27" }, { "n": 4, "id": "fn-america-llc-26c454", "title": "Instructions for FN SCAR 16S and 17S Barrel Change (63903, 2303)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/08/SCAR-Carbine-Accessory-Barrel-Instructions_63903_2303-1.pdf", "accessed": "2026-09-27" }, { "n": 5, "id": "fn-america-llc-777b9d", "title": "Instructions for FN SCAR Non-Reciprocating Charging Handle Kit (FN002 R3)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2024/02/FN002-SCAR-NRCH-Instruction-Manual-R3-05-20-2269.pdf", "accessed": "2026-09-27" }, { "n": 6, "id": "fn-america-llc-8612bb", "title": "Instructions for FN SCAR-SC Rear Stock (2407)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2025/02/2407_FNSCAR-SC-Stock-Install.pdf", "accessed": "2026-09-27" }, { "n": 7, "id": "fn-america-llc-ff235d", "title": "FN SCAR 16S/17S/20S Owner's Manual (2512)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/wp-content/uploads/2026/01/2512_FNSCAR_16S17S20S_OM_.pdf", "accessed": "2026-09-27" }, { "n": 8, "id": "fnamerica-specs-629cb4", "title": "FN SCAR® 17S NRCH — product page (Specs / Primary Features)", "publisher": "FN America, LLC", "reliability": "primary", "url": "https://fnamerica.com/products/rifles/fn-scar-17s-nrch/", "accessed": "2026-10-03" }, { "n": 9, "id": "tier-a00e0648", "title": "Autoloading Rifle Owner's Manual FN SCAR 16S and 17S (2016)", "publisher": "FN America", "reliability": "primary", "url": "https://s3.amazonaws.com/files.ammunitiondepot.com/fn-firearms/carbines-discontinued/fn-scar-16s-17s-owners-manual-2016.pdf", "accessed": "2026-10-29" } ] }