Mk17 Mod 0 clone build: SOCOM's FN SCAR-H, part by part

In June 2010, SOCOM stopped buying the 5.56 SCAR and kept the 7.62 one. That rifle, the Mk17 Mod 0, stayed on order from FN Herstal in Belgium until at least 2019. Photos show it with Rangers, SEALs and Green Berets from 2009 to at least 2019. In May 2026, SOCOM named its replacement.

You can't buy the issued rifle, but you can get close with an FN SCAR 17S. Below is every issued part we could document, what we'd buy in its place and what no civilian can own.

What a Mk17 Mod 0 clone copies: SOCOM's 7.62 SCAR

Your clone copies the MK 17 MOD 0 7.62mm SOF Combat Assault Rifle, Heavy, better known as the SCAR-H. The service rifle is select fire, flat dark earth and sold to the military only.

FN's specification gives you most of the build list. The barrel is 16 inches, cold hammer forged and chrome lined, and swaps in under five minutes. Add a short stroke piston with an adjustable regulator, rails at 3, 6, 9 and 12 o'clock, folding iron sights and a side folding stock.

What you can't copy is the select fire trigger module, the issued suppressors and the military IR lasers. We flag each one where it comes up.

Mk17 SCAR-H history: from the 2004 contract onward

By Wikipedia's account, SOCOM opened the SCAR competition in early 2004. FN says nine vendors submitted a dozen designs and its entry was the only one to meet every go or no go criterion.

SOCOM signed with FN Herstal S.A. on November 5, 2004, after a competition that drew 12 offers. The family split into the 5.56 Mk16 and the 7.62 Mk17.

Who carried it: Rangers, SEALs and Green Berets

FN says the Mk16, Mk17 and Mk13 grenade launcher began fielding to SOF units in early April 2009. Wikipedia, citing a May 2009 Army Times report, says a 75th Ranger Regiment battalion took about 600 SCARs to war that year. We couldn't retrieve the article, and the figure doesn't split Mk16s from Mk17s.

Navy photos show SEALs with the Mk17 in Zabul province, Afghanistan, in April 2010 and in California in January 2012. A 2019 DVIDS photo shows a 3rd Special Forces Group Green Beret firing one at a 550 meter target. MARSOC use rests on owners' photo threads only.

Why SOCOM kept buying the Mk17

On June 25, 2010, SOCOM stopped buying the Mk16 after 850 of them and 750 Mk17s. The requirement had called for 38,000 Mk16s and 5,600 Mk17s. Our Mk16 Mod 0 SCAR-L clone build covers that side of the story.

The Mk17 became SOCOM's single SCAR. FNH USA told Shooting Illustrated in 2011 that the bigger Mk17 receiver became the base, because a 5.56 receiver can't be scaled up. FN had finished a 5.56 kit for it in late 2010.

NSWC Crane kept ordering complete Mk17s from FN until at least May 2019, and spares until at least May 2023.

Is the Mk17 being replaced?

Yes. A SOCOM spokesperson told Task & Purpose in May 2026 that the MK24 Mid-Range Gas Gun-Assault is "a direct replacement for the MK17," already in production and due to start fielding in fiscal 2026. It fires 7.62 and 6.5 Creedmoor.

Its name matches the Mid Range Gas Gun Assault category SOCOM began assessing in 2021. SOCOM gave LMT Defense of Iowa a 10 year contract worth up to $92 million for it in August 2025, as Shooting Illustrated reported. FN America said in October 2025 that its military SCARs were still in production, so expect Mk17s in service for a while yet.

Mk17 variants: CQC, STD, LB and the 5.56 kit

Each Mk17 could take a 13 inch CQC barrel, the 16 inch standard or a 20 inch LB, and a swap takes minutes. SOCOM's contract records show CQC barrels on order from September 2008 and LB barrels from April 2009.

Mk17 LB vs the Mk20 SSR

The LB is a 20 inch barrel on a standard Mk17. The Mk20 Sniper Support Rifle is its own rifle, with a longer receiver, a stronger barrel extension, a heavier barrel and an upgraded trigger.

The 20 inch idea grew into the Mk20, and SOCOM approved Mk20 full rate production in late October 2010, according to Jane's as Wikipedia cites it. FN's 20 inch 17S barrel assembly, carded below, gives you the LB look.

Converted Mk17s in 5.56

SOCOM ordered FN's 5.56 conversion kits in May 2011, September 2013 and August 2014. Owners spot converted rifles mostly with the 75th Ranger Regiment, and an armorer says they came with 30 round Mk16 steel magazines. So a 5.56 SCAR in a photo from after 2013 may well be a Mk17.

The kit was never sold to civilians, as far as owners know. Don't confuse it with the "MK 17 WEAPON CONVERSION KIT" orders to UTM Limited. Those look like training round kits, though that reading is an inference. If you'd rather build a short 5.56 carbine, start with our Mk18 Mod 0 CQBR guide.

Early and late Mk17s, 2009 to 2019

The first rifles came from a small low rate order for "SCAR H (S)" rifles in September 2007. Contract titles show selector bodies retrofitted in 2009, and some 2015 deliveries came without basic issue items.

Owners split the muzzle and can into two eras: an AAC 18 tooth hider and AAC SCAR-SD early, then FN's three prong hider and an FN can from about 2012. One armorer disputes the early half, so treat the split as owner history. Pick one era and copy it consistently.

How to build a Mk17 clone: start with a SCAR 17S

The service Mk17 is select fire and not for sale, so your build starts with FN's semi auto SCAR 17S. It arrives with the stock, rails, sights, carrier and charging handle your clone needs.

FN ended its commercial legacy SCAR line in October 2025, so you're shopping for a used rifle or one of the last new ones. We now list the legacy FDE 17S, but no merchant had one in stock on September 27, 2026. The one 17S in stock in our merchant feeds that day was listed as an updated model, so confirm the generation before you buy.

We checked our own build data too. Of the carts created on GunPartPicker from December 10, 2025 to September 27, 2026, seventeen held a SCAR-H family part, all of them made between December 13, 2025 and June 10, 2026. None was a SCAR build. The barrels sat in AR-15 and AR-10 builds, because our builder has no SCAR platform yet. The one click box at the top loads the Elcan, laser, light, hider, grip and can for a 17S you buy complete. Use the product cards here instead.

Pick a legacy FDE 17S with a reciprocating handle

The closest host is a legacy FDE 17S with the reciprocating charging handle. Later legacy NRCH models have a static handle, and a Mk17's handle rides with the carrier. The 17S barrel is 16.25 inches against the Mk17's 16, and nobody can see the difference.

Our cards are the FDE 17S, MPN 98541, and its US marked twin, 98541-1. Neither had an offer when we checked.

Purists hunt for Belgian made imports, since every issued rifle order we traced went to Belgium. Keep the semi auto trigger module, and leave FN's serial number and required markings alone. Replica Mk17 roll marks and IUID labels on clones are cosmetic.

Why the 2026 SCAR 17S looks wrong

FN announced a redesigned SCAR line on January 15, 2026. The new 17S has a longer receiver with an M-LOK rail, a compensator, non reciprocating charging handles and a hydraulically buffered carrier. None of those were on a Mk17, so skip it for a clone.

Mk17 parts list: the issued part and what to buy

Here's every slot we could document, what we'd buy and how close it gets. We cross checked each row against an enthusiast Mk17 Mod 0 parts list and corrected it where records or photos disagree.

Product photography is supplied by the listed merchants through their affiliate feeds.

Exact is the issued part or its commercial twin, and equivalent looks and works the same from another maker. On host means it comes with a 17S, and unobtainable means no civilian can buy it.

The lower receiver group

On a SCAR, the lower is a polymer trigger module housing, and most of what sits here arrives on your 17S.

Lower receiver: FN trigger module and enlarged guard

The issued part is FN's select fire Mk17 trigger module in FDE. Owners say issued rifles mostly use the 90/180 degree selector pattern, and FN sells the auto frame, P/N 3185110020, only to SOT licensees and law enforcement.

FN lists an enlarged trigger guard, so the "Trigger Guard: N/A" on the enthusiast list undersells it. The guard is part of the module. Keep your 17S module. The Handl Defense and "Stryker SEAL" lowers on that list are civilian aftermarket parts that were never issued.

Trigger: FN factory or Geissele Super SCAR

Issued Mk17s keep FN's standard trigger, according to the armorer posting from Afghanistan. FN's semi auto SCAR trigger assembly is the closest part you can buy, an equivalent of the issued select fire group, at $144 from Primary Arms when we checked.

The Geissele Super SCAR shows up on plenty of clones, including the top YouTube result when we searched "SCAR 17 clone". It's a civilian upgrade, like the Timney SCAR17, and no source shows either as standard issue.

Stock and grip: FN side folder, A2 profile grip

Your 17S has the issued style stock: FN's side folding, telescoping polymer stock with an adjustable cheekpiece. A rare fixed FDE stock also exists, and FN was paid for fixed stock engineering in May 2009. Owners say the folding latch is the weak point, and FN revised it.

The SCAR lower takes an M16 compatible grip, and the issued one is FN's A2 profile grip in FDE. The Brownells A2 grip in FDE is an equivalent, and it cost $3.99 when we checked.

The upper receiver group

A SCAR has no separate gas block, handguard or front sight to buy. The AR style rows for them on the enthusiast list fold into the parts that carry them.

Barrel and gas block: FN 13, 16 and 20 inch

The standard barrel is FN's 16 inch, cold hammer forged and chrome lined. The gas system rides on it, with a short stroke piston, an adjustable regulator and the folding front sight. Your 17S ships with a 16.25 inch version.

For the CQC and LB looks, FN built 13 and 20 inch 17S barrel assemblies, MPN 98814 and 98818. Both are the civilian versions of the issued lengths, and neither had an offer when we checked. FN says legacy barrel supply will be limited over the next five years, and the 13 inch makes an SBR, so check your state's law before it goes on.

Muzzle device: AAC 18T or FN ECP three prong

The record here is disputed. Most owner posts put an AAC 18 tooth hider on early rifles and FN's three prong hider, called the ECP, on rifles from about 2012. One armorer wrote that the AAC hider was on Mk16s and the standard FN hider on Mk17s. The contracts, including 1,121 hiders bought in May 2011, never name a maker.

FN sells a SCAR 17 three prong hider with a suppressor mount, P/N 3181380110, threaded 5/8x24. Owners treat it as the ECP, though FN's listing never says so, and we don't carry it yet. If you buy a surplus AAC 18T, inspect it, because one builder got one in 2025 that looked like a rewelded demil.

Neither card is the ECP. The SureFire FH762SV-SCAR is the Mk20 hider seen on at least one Mk17. The SF3P-762 is an equivalent three prong that SureFire sells as a SOCOM suppressor adapter.

Rails: FN side rails and the PWS SRX extension

The Mk17 has an integral top rail plus removable rails at 3, 6 and 9 o'clock, and so does your 17S. One owner in the clone thread calls the PWS SRX the most common extension in service. We don't carry it, or the FN prototype rail a few fielded rifles wore.

Our cards are modern stand ins: KDG's MREX Mk II as an equivalent, and a generic TangoDown rail cover as a budget pick.

Bolt carrier group and charging handle

Both come on the 17S. The Mk17 uses FN's reciprocating charging handle, mountable on either side, so skip NRCH carriers and the 2026 buffered carrier. Stories of broken handles trace to a forum rumor, and the one armorer data point we found is a single bent handle in four years.

Iron sights: FN folding front and rear

The front sight folds on the gas block, so it comes with every barrel assembly, and the "Front Sight: N/A" on the enthusiast list misses it. The folding, removable rear sight ships on your 17S too.

Mk17 optics: Elcan, EOTech, Nightforce and Leupold

SOPMOD designations are documented, but which sight rode on which Mk17 comes from photos and owner posts. Pick the era you're copying first.

Elcan SpecterDR 1.5x/6x with a 7.62 BDC

An armorer in the clone thread says Mk17s are supposed to be issued the Elcan SpecterDR 1.5x/6x with a 7.62 BDC. Owners call it the SU-230B. He says the 1x/4x Elcans carried a 5.56 BDC for M4A1 uppers, so the magnification follows caliber, not barrel length.

We cover the M4A1 URGI uppers and their 5.56 Elcans in their own guide.

A coalition security force member, as the Army caption describes him, watches from cover in Tsamkani district, Paktiya province, Afghanistan, on April 17, 2013; under the hand painted camouflage his receiver is marked MK 17 MOD 0, and the rifle carries an Elcan Specter, an AN/PEQ-15 laser and a weapon light. U.S. Army photo by Pfc. Codie Mendenhall, Combat Camera Afghanistan, public domain, via Wikimedia Commons.

Our cards are the exact 7.62 Elcans in FDE. The 1.5x/6x was $3,718 at Optics Planet when we checked, and we've added the 7.62 1x/4x, though which reticle a 1x/4x on a Mk17 carried isn't settled.

Wikipedia's SOPMOD list pairs the 1x/4x, the SU-230/PVS, with a Docter mini red dot, and clones often add a Docter Sight II+. We don't carry a rifle Docter sight yet.

EOTech EXPS3 and 553 with the G33 magnifier

Wikipedia's SOPMOD list gives the EOTech 553 as the SU-231/PEQ and the EXPS3-0 as the SU-231A/PEQ, and owners pair both with 3x magnifiers on the Mk17. We carry the tan EXPS3-0, an exact match, and the tan G33 as an equivalent, since no source names the issued magnifier.

The 553.A65 we list is exact but had no offer when we checked. Our SOPMOD Block II M4A1 guide lists the same EOTech and Elcan options.

Nightforce NXS 2.5-10x24 and Leupold Mark 6 3-18x44

The best documented scope is the Leupold Mark 6 3-18x44. SOCOM's ECOS-O award of March 19, 2013 went to Leupold for it, for the M4A1, Mk16, Mk17 and other rifles. A 2019 Army photo shows a Leupold scope on a Green Beret's Mk17.

A Green Beret from 3rd Special Forces Group (Airborne) fires a Mk17 SCAR-H at a 550 meter target near Nellis Air Force Base, Nevada, on August 23, 2019; the rifle wears a Leupold scope in a Leupold marked one piece mount and rests on a bipod. U.S. Army photo by Sgt. Steven Lewis, public domain, via DVIDS.

Owners put the Nightforce NXS 2.5-10x24 on SEAL rifles, but only community posts back it. We don't carry that scope, so the NXS Compact 2.5-10x42 stands in, with the same magnification and a bigger objective.

The Mark 6 we list had no offer when we checked, and the Mark 5HD 3-18x44 is an equivalent that needs 35mm rings. The clone thread also lists an NXS 3.5-15x50, and a few photos show an FDE ATACR 1-8x24.

If a dedicated 7.62 precision rifle is your real goal, our M110 SASS guide is the next read.

Scope rings and mounts that clear the rear sight

No document shows the issued ring height. Treat this row as weak. For the NXS 2.5-10x24, owners name a Wilcox MRDS mount with Nightforce Ultralite rings, or Badger's 1.25 inch EBR ring, P/N 306-29. One calls the 1.265 inch Nightforce A108 clone correct.

Neither clears the Mk17's rear sight, so builders who want it usable run the 1.375 inch A110. The A107 on the enthusiast list sits lower, at 1.125 inches. For the Mark 6, owners list Leupold mount P/N 120303.

The enthusiast list also names Badger's 306-10, a 1.40 inch ring. We carry all three Nightforce heights and both Badger rings, though the 306-29 had no offer when we checked. We don't carry the Wilcox or Leupold mounts yet.

Mk17 accessories and issue items

Where a part is law enforcement only or long gone, we say so and point you to the closest civilian stand in.

Light and laser: Insight M3X, WMX200 and PEQ-15

The lights are Insight's M3X, the SOPMOD SU-233/PVS, and the WMX200, and neither is in any feed we read. The lasers are the AN/PEQ-15 and the high power LA-5/PEQ. Lasers of this class are sold to law enforcement and the military only.

Your stand ins are tan SureFire Scout lights and two commercial lasers civilian retailers list, the L3Harris ATPIAL-C and the Steiner DBAL-A3. All four cards are equivalents. Our CQBR Block II clone guide covers the same SOPMOD Block II lights and lasers.

Suppressor: AAC SCAR-SD, FN QD 701 and SureFire

FN supplied the Mk17's suppressors on SOCOM orders from April 2009 through 2015, and the contracts never name who built them. Owners put the AAC SCAR-SD on early rifles and an FN can they call the QD 701 on later ones. SureFire FA762SV cans show up on some too, probably borrowed from Mk20s.

A Navy SEAL trains with a suppressed Mk17 in a remote area of California in January 2012; the receiver is marked FN HERSTAL BELGIUM and MK 17 MOD 0, and the rifle carries a compact variable scope and an AN/PEQ-15 laser with a pressure switch. U.S. Navy photo by Mass Communication Specialist 2nd Class Martin L. Carey, public domain, via Wikimedia Commons.

None of those cans is sold new. The practical stand in is a SureFire SOCOM762-RC2 on the SF3P-762 mount above, though we couldn't confirm the RC2 locks onto the older FH762SV. Both RC2 cards are equivalents, and like any can they're NFA items, so check your state's law first.

Foregrip and bipod: TangoDown, Harris and Atlas

The clone thread's parts list names a tan TangoDown vertical grip or a KAC grip, and our TangoDown cards are exact brand matches in FDE. We found no service photo of the Grip Pod on the enthusiast list.

A Mk17 captured in Kunduz wore a Harris bipod. Clones often run an Atlas BT10, made by B&T Industries, LLC of Kansas, a different company from Swiss B&T AG, though no photo shows one in service. Our Harris 1A2 card mounts on a sling swivel stud, so add a Picatinny adapter for the SCAR rail. The Atlas BT10 V8 card comes with a 1913 rail clamp.

Magazines, sling and the Mk13 EGLM

The Mk17 takes FN's proprietary 20 round steel magazine, and SOCOM ordered its own "MK 17 MOD 0" version in May 2013. The exact match is FN's 20 round steel magazine in FDE. Every FN steel magazine in our feeds was out of stock, though FN says legacy 17S magazines will stay available. Amend2's Mod 3 and ProMag's FDE polymer magazine are budget stand ins.

The sling is weak evidence. One owner gives a tan FN sling as P/N 314-910-0030, and we couldn't verify it. The Mk13 Mod 0 grenade launcher mounts under either SCAR, but it's service context, not a part you can build.

Owners also run Blue Force Gear slings, and our cards are two Vickers models in coyote brown as equivalents.

The civilian legal path to a Mk17 clone

The service Mk17 is a machine gun. Your clone is a semi auto 17S, and its three barrel lengths lead to different rules.

The 13 inch CQC barrel makes an SBR

A 13 inch barrel on a SCAR 17S makes a short barreled rifle. ATF announced on October 9, 2026 that it would stop enforcing SBR registration and approval, but your state has to allow SBRs, and some only allow registered ones. Taking it across state lines still needs an approved ATF Form 5320.20.

A pinned and welded muzzle device won't save you, because a normal flash hider can't carry a 13 inch barrel to 16 inches. The 16.25 inch barrel your 17S ships with and FN's 20 inch assembly need no NFA paperwork.

Suppressors, IR lasers and select fire parts

Every suppressor in this guide is an NFA item, though ATF announced on October 9, 2026 that it would stop enforcing NFA approval for them. Check your state's law first. Our suppressor guide covers the current federal rules, tax included.

IR lasers like the AN/PEQ-15 and LA-5 are law enforcement or military sales, so you'll need a civilian legal aiming device. No automatic fire control part belongs in your rifle. Several states also restrict folding stocks, flash hiders and detachable magazines, so check yours first.

What you can buy today and what is unobtainable

We sorted the 56 issued parts and variants we researched by what we could offer you on September 27, 2026. About a sixth isn't in our catalog yet, and a fifth no civilian can buy.

Parts no retailer can sell you

The select fire rifle, its auto trigger module, the AN/PEQ-15 and the LA-5/PEQ are military or law enforcement items. The issued FN and AAC suppressors aren't sold new, FN's 5.56 kit never reached civilians, and the Mk13 launcher is service context only.

SureFire's FA762 cans and Insight's lights are rare secondhand finds, and a surplus AAC 18T is a gamble.

What a Mk17 clone costs today

We priced the add on parts for a later Mk17 with an Elcan, laser, light, grip and can, using in stock prices on September 27, 2026. The 17S isn't in the total, since no merchant had one in stock.

Swap the Elcan for the tan EXPS3-0 at $815 and a G33 at $527.68, and the parts total drops to $3,614.65. Your 17S and magazines come on top.

What the internet gets wrong about the Mk17

Here's what popular articles and clone lists say, and what the records and owners show.

Made in Belgium, not South Carolina

Wikipedia names FN America in Columbia, South Carolina as the Mk17's maker. Every SOCOM and NSWC Crane Mk17 rifle and parts order we found, from 2007 to 2023, went to FN Herstal S.A. in Belgium. Crane's 2011 sole source notice names FN Herstal in Belgium too.

The SEAL rifle in the 2012 photo above wears an FN HERSTAL BELGIUM roll mark. We found no SCAR or Mk17 award to FN America in federal contract data.

Dates and numbers the popular articles get wrong

A 2024 19FortyFive article says the Rangers got the Mk17 in early 2008, one battalion 600 of them, and that it beat the M4 in the 2007 dust test. FN puts fielding in April 2009, the 600 figure doesn't split Mk16s from Mk17s, and that Aberdeen test compared 5.56 carbines.

Rate of fire varies too: 550 rounds a minute in Wikipedia's infobox, 625 at AmericanSpecialOps and 600 from FN. The Mk17 was meant to replace the M14 family and the Mk11, but it supplemented them, and operators chose which to carry. We cover the Mk11 Mod 0, the rifle the Mk17 was meant to replace, in its own guide.

The Kunduz Mk17 in Taliban propaganda from 2015 wasn't proof of US losses in Nangarhar either. TFB traced it to 2015 fighting involving Afghan NDS or ANA units.

Parts the clone lists get wrong

The enthusiast list we lean on needs a few fixes. Its "Gas Block: N/A" and "Front Sight: N/A" miss the gas block front sight. Its "SU-230A" Elcan is the SU-230B to most owners, and its "Trijicon Ta101 NSN" matches no Trijicon model we could find.

Other lists slip too. The SCAR-H takes FN's own magazines, and SR-25 pattern lowers for it are aftermarket. Geissele triggers and Handl lowers are civilian parts, and no source we found shows either on an issued Mk17.

Sources and photo credits