Mk13 Mod 5 clone build: SOCOM's AICS .300 Win Mag, part by part

In 2009, engineers from NSWC Crane put a tan, folding .300 Win Mag bolt gun on a briefing slide and captioned it MK 13 MOD 5.

You can build a close clone today, but not from new parts alone. You'll hunt for its chassis, night sight mount and suppressor secondhand.

What a Mk13 Mod 5 clone copies

A Mk13 Mod 5 clone copies the SOCOM sniper rifle NSWC Crane assembled from parts. Four things give it away: the tan AICS 2.0, a Remington or Stiller long action, a Lilja barrel contoured for the Mk11 can, and a MARS rail or Badger IMUNS carrying the night sight.

Pick an era before you buy anything, since early and late rifles used different actions, triggers and rails.

Mk13 Mod 5 parts list: the issued part and what to buy

Here's every slot, the issued part as the records or owners give it, and what you can buy. We cross checked an enthusiast Mk13 Mod 5 parts list and borrowed its slot names.

Eight of the parts GunPartPicker lists for this build, most of them stand ins, laid out overhead. The product photography is supplied by the listed merchants through their affiliate feeds.

Sold new means you can still buy the issued model. Stand in only means you can't, though a similar product exists, and secondhand only means nothing new comes close. Evidence runs from strong (Crane, the makers or several sources) to weak (one owner post).

Mk13 Mod 5 history: Crane's folding .300 Win Mag for SOCOM

Earlier Mk13s bedded a Remington 700 long action in a McMillan fiberglass stock. The Mod 5 moved the same action and cartridge into AI's folding chassis.

Why a .300 Win Mag in a folding AICS chassis

Reach drove the cartridge. Crane's 2009 briefing gives the 190 grain A191 load, known as Mk 248 Mod 0, a published effective range of 1,200 yards. Crane picked a 220 grain Sierra MatchKing load, Mk 248 Mod 1, to stretch that to 1,500.

The AICS 2.0 did away with bedding. It adjusts to fit you, and it folds, taking 210 mm off the rifle's length.

Who carried it: SEALs, Army Special Forces and MARSOC

Navy SEALs, Army Special Forces and MARSOC all used Mk13 rifles. In May 2018 Marine Corps Systems Command called the Mk13 MARSOC's primary sniper rifle, without naming a Mod.

Photo captions rarely name it either. A 2020 MARSOC photo says only Mk13, and by then that could mean a Mod 7.

A Navy SEAL aims a rifle with a tan AICS chassis during land training in California, January 2012. The setup is consistent with a Mk13 Mod 5, but the Navy caption doesn't name the rifle. U.S. Navy photo by Mass Communication Specialist 2nd Class Martin L. Carey, public domain, via Wikimedia Commons.

Mk13 Mod 5 variants: early, late and mixed rifles

The Mod 5 changed while it served. Owners and builders describe two patterns, plus rifles that crossed them.

Early rifles: Remington action, Walker trigger, MARS rail

Early rifles paired a Remington 700 long action, which owners say Crane blueprinted and fitted with an M16 style extractor, with the Remington factory trigger. A three sided MARS 20 MOA rail ran over the action and forward over the chassis to carry a clip on night sight.

Crane's 2009 photo shows a long rail reaching over the forend, and americanspecialops confirms the Remington action and the MARS.

A SEAL Team 1 sniper shows Navy family support staff the weapons SEALs deploy with, San Diego, 29 July 2010. The camouflage painted rifle in the middle, an AICS chassis bolt action with a long top rail over the forend, an over the barrel suppressor and a Harris type bipod, is consistent with a Mk13 Mod 5 in its MARS rail setup, though the Navy caption doesn't name it. U.S. Navy photo by Mass Communication Specialist 2nd Class Shauntae Hinkle-Lymas, public domain, via Wikimedia Commons.

Late rifles: Stiller action, XTSP trigger, Badger IMUNS

By July 2011 Crane had bought Badger Ordnance's IMUNS for the Mod 5, Soldier Systems Daily reported. It holds the night sight on the forend, so the day scope sits on a plain 20 MOA action rail, a full inch lower.

Owners say later rifles also got Stiller Mk13 actions, trued with the extractor work done, and two stage XTSP triggers. Stiller says Crane first approached it about the Mk13 in 2010, but nobody dates the switch on the Mod 5.

Rifles that mixed the two patterns

Not every rifle fits a pattern. One owner says a few issued rifles paired the Remington action with the IMUNS, and High Caliber Sales built customer rifles that way in 2012. Raven Rifles lists a Stiller on a MARS rail.

The action, trigger and AICS 2.0 chassis

Start with the action, since it decides your era.

Action: Remington 700 long action or Stiller Mk13

An early rifle needs a Remington 700 long action with a magnum bolt face. A late one needs Stiller's Mk13 long action. The enthusiast list specifies a G prefix Remington and a 2019 seller's clone used an A prefix, but no source ties either prefix to issued rifles.

We don't stock bolt action receivers or Badger's M16 extractor kit, though both are sold new. A 2022 Sniper's Hide reply says Stiller had just been sold, so check who makes Mk13 pattern actions now.

Trigger: Remington Walker or XTSP two stage, by action

The enthusiast list doesn't pair its two triggers with actions. Owners do: the Remington factory trigger on Remington rifles, XTSP's two stage MK 13 Model 22 on Stiller rifles. A 2024 Sniper's Hide review puts the Model 22 in the Mod 5.

Neither issued trigger is sold. The same review calls XTSP's commercial Mod 22 quite similar to the Mk13 version, and TriggersAndScopes listed it at $360 on 27 September. It's the closest thing to a late rifle's trigger, though we don't stock it.

Our cards are Remington 700 stand ins. Take a TriggerTech two stage for a late build or the Timney single stage for an early one.

The Timney was out of stock on 27 September.

Chassis: AICS 2.0 in Dark Earth or Pale Brown

The issued chassis is AI's AICS 2.0 for the Remington 700 long action, with tan polymer panels. Its color name is disputed. One owner says only the early Pale Brown is correct. The enthusiast list and Raven Rifles say Dark Earth, and AI's only Pale Brown listing we found is for a Mod 7 chassis.

You won't find a new AICS 2.0. Real ones surface in surplus deployment kits, chassis and accessories without a barrel or receiver.

Our cards are budget stand ins, Magpul's Pro 700L in FDE. The folding version is the closer match, at $844.19 on 27 September. The fixed one doesn't fold.

Recoil lug: a Crane part with a disputed shape

One owner's build guide says Crane made an L shaped lug for the Mod 5, and that Red Bull Armory makes a replica. A collector on Sniper's Hide says L lugs belonged to the Mod 0, 1 and 3, and chassis rifles like the Mod 5 used a straight .25 inch lug.

Each claim rests on one person, and we found neither Crane lug for sale. Ask your gunsmith what your chassis takes.

Magazine: the 5 round legacy AICS box

The americanspecialops page gives the Mod 5 a 5 round magazine, and Wikipedia says AI's .300 Win Mag magazines are 5 round single stacks. You want the legacy AICS pattern, not AI's AX magazine. Brownells had AI's version at $98.99 on 27 September, and Magpul's PMAG 5 AC L Magnum, our budget card, was $32.99.

The Lilja barrel and the KAC Mk11 suppressor

Raven Rifles, a builder, singles out the barrel taper as a hard part to copy.

Barrel: Lilja stainless, 26.5 inch, 1 in 10, Mod 5 contour

The issued barrel is a bead blasted Lilja stainless .30 caliber with a 1 in 10 twist. Sources split on length: americanspecialops, High Caliber Sales and RW Snyder give 26.5 inches finished, and the enthusiast list and Raven Rifles give 26.

Lilja still sells its stainless MK13 blank with a Mod 5 contour option. Its mk13_mod5 drawing shows a 28 inch blank running from a 1.200 inch shank to .794 inch at the muzzle. The stock blank is 4 groove, but nobody documents the issued groove count.

We don't stock Lilja barrels, so you'll order the blank direct and have your gunsmith chamber it.

Muzzle device: none, only notches for the Mk11 latch

The Mod 5 has no flash hider or brake, and the enthusiast list has N/A. One 2018 owner describes notches cut into the barrel for the Mk11's gate latch, plus a .125 inch index pin at 6 o'clock, and says it uses no Mk11 gas block.

On the SR-25 that latch grabs the gas block, per a Big Tex Ordnance listing, so on a bolt gun the notches stand in for it. AAC's Mk13-SD brake and can belong to the later Mod 7.

Suppressor: the KAC Mk11, not the M110 can

The Mod 5's can is Knight's Armament's Mk11, dealer part 98440-BLK, the over the barrel suppressor SOCOM issued with the Mk11 Mod 0, source of the same suppressor.

IMFDB calls it a KAC M110 can, but KAC lists that can for rifles with the M110 flash hider only, and the Mod 5 has none. See the M110 SASS and the flash hider its can needs.

The Mk11 trades only on the NFA secondhand market. Our card is a stand in: KAC's current 7.62 DTS-1.1, a direct thread can, so your barrel gets threaded 5/8-24 instead of notched.

Chamber and Mk 248 match ammunition

The chamber is this rifle's least documented part. The ammunition is among its best documented.

Chamber: .300 Win Mag with an unpublished throat

We found no published reamer spec for the Mod 5. A 2019 seller called his clone's chamber a correct A191 cut, for the 190 grain load. A 2018 owner said he'd need the Mk 248 Mod 1 reamer to cut it himself.

An AR15.COM post warns that the 220 grain Mod 1 might spike pressure in any Mk13 chamber but a Mod 7's. Crane's briefing says it can be fired in existing weapons, on the same slide as the Mod 5. Follow your barrel and reamer makers' specs over either claim.

Ammunition: 190 and 220 grain loads you can buy

The issued loads were Mk 248 Mod 0, DODIC A191, with a 190 grain Sierra MatchKing, then Mk 248 Mod 1, DODIC AB43, with a 220 grain MatchKing. You can't buy either military load.

Our stand in cards match the bullet weights. Federal Gold Medal loads the same 190 grain MatchKing, and Barnes' 220 grain load uses its own OTM bullet. Our .300 Win Mag ammo page tracks the price per round.

The day scope, scope base and rings

Owners tie the scope to the unit, and the enthusiast list ties the rings to the rail.

Scope: Nightforce NXS or the Schmidt and Bender PSR

No single scope was issued. One owner says SEALs and MARSOC ran the Nightforce NXS 5.5-22x56 and Army Special Forces the NXS 3.5-15x50. Owners also put Schmidt and Bender's PM II 5-25x56 on Mod 5s. SOCOM picked a modified version for its Precision Sniper Rifle in 2011, per AccurateShooter.

Our cards are the commercial NXS models. The enthusiast list calls the 3.5-15x50 a first focal plane F1, but we couldn't verify that, and ours is second focal plane.

The military S&B, with the Tremor2 reticle owners describe, isn't sold. Optics Planet listed a commercial PM II 5-25x56 with a P5FL reticle at $3,989 on 27 September. It's a stand in, not the PSR scope.

Scope base: MARS rail or a 20 MOA action rail

Early rifles used a three sided MARS 20 MOA rail. Nobody has settled who made the issued ones: Remington advertised MARS on the M24A2, BG Defense credits McCann Industrial with the design, Raven Rifles writes Remington/Badger, and IMFDB says MIRS.

IMUNS rifles used a plain 20 MOA action rail, a Nightforce per High Caliber Sales and the enthusiast list, or a Stiller per the same list. Nightforce's long action bases started at $59.00 on 27 September. Our cards are its X-Treme Duty and Standard Duty 20 MOA bases, since no source names the model on issued rifles. We found no MARS rail sold new, though BG Defense lists a clone.

Scope rings: Nightforce A108, or a LaRue LT111 for 34 mm

The enthusiast list names Nightforce's A108, the 1.265 inch intermediate 30 mm UltraLite set, for MARS rifles with NXS scopes. For the 34 mm S&B, one owner names LaRue's LT111 OBR QD mount, which Optics Planet listed at $239.46 on 27 September. Ring height on IMUNS rifles is still an open forum question.

Our cards are the A108 itself and the LT111.

The forend: IMUNS, night sight, laser and bipod

On a late rifle the IMUNS replaces the AICS bipod block, so the bipod, clip on sight and laser all hang from it.

Night sight mount: the Badger IMUNS and its clip on

Badger's installation sheet gives the IMUNS part number 1005-310-10, for AI rifles and AICS chassis. It's a forend mount for in line clip ons such as the AN/PVS-22, 24 and 27, with removable side rails.

We found no IMUNS for sale new. A 2024 Sniper's Hide post says Badger discontinued it, though one reply pointed to a Brownells backorder. None of our feeds sells the PVS sights, so our card is a thermal stand in.

Laser: an ATPIAL or DBAL on the side rail

Soldier Systems Daily says the IMUNS side rails were made for lasers such as the ATPIAL and DBAL. The ATPIAL is the AN/PEQ-15, and the enthusiast list adds the AN/PEQ-2A and LA-5. Our ATPIAL and LA-5 listings are for law enforcement only.

Our card is the civilian DBAL-A3, a stand in. It's a staple of AR builds on GPP, with 283 adds in 206 sessions from 31 January to 27 September 2026.

Bipod: a Harris swivel with 6 to 9 inch legs

Crane's 2009 photo shows a Harris type bipod on the front stud, and owners name the Harris S-BRM, a swivel model with notched 6 to 9 inch legs. The enthusiast list writes it BRMS. Eight merchants in our feeds had it in stock on 27 September, from $99.73. The budget 1A2-BRM has the same legs on a fixed base, without the swivel.

Mk13 Mod 5 vs Mod 0, and the Mod 7 after it

The Mod 5 sits between the McMillan stocked Mod 0 and the Marine Corps Mod 7.

StrategyPage called the Mk13 a customized SOCOM M24 in 2013. It shares the M24's action family and the M24A2's MARS rail, but Crane gave it its own barrel, chassis and can. We found no source saying Mod 5s were converted M24s.

Mod 0: the McMillan stocked rifle before it

The Mod 0 bedded a trued Remington 700 long action in a McMillan A2 fiberglass stock around a Crane L lug, with an internal magazine and, later, a McCann MIRS rail. It fired the 190 grain Mk 248 Mod 0. A Crane gunsmith told a collector that most were never suppressed. See the McMillan stocked Mk13 Mod 0 that came before it.

Mod 7: the Marine Corps rifle adopted in 2018

In April 2018 the Marines planned to buy 356 Mk13 Mod 7s to replace the M40, Marine Corps Times reported. The Mod 7 puts a Stiller action in AI's aluminum Mod 7 chassis, with its own Lilja taper and Win Mag cans from SureFire and AAC.

Summaries that call the Mk13 a Marine scout sniper rifle mean the Marine Corps Mk13 Mod 7. Late Mod 5s had Stillers too, so check the chassis before you call a rifle a Mod 7.

What the internet gets wrong about the Mk13 Mod 5

Here's what clone sellers, IMFDB and rail sellers call these parts, and what the sources show.

Chris Kyle's own account never names a Mod 5

Charlie's Custom Clones says Chris Kyle mainly used a Mod 5 in Iraq, which it calls an AI AW. IMFDB and Wikipedia describe his Mk13 as the McMillan stocked Mod 0.

Kyle's book, as PrecisionRifleBlog quotes it, says his first .300s had McMillan stocks and his platoon got new ones in Accuracy International stocks for Ramadi in 2006. He gives no Mod number, and a Mod 5 is no AW. Our Mk13 Mod 0 clone build covers Kyle's rifles.

Traditional stocks and 10 round magazines are not Mod 5

The same site says the Mod 5 used a more traditional stock and a Pac-Nor barrel. Crane's 2009 photo shows the AICS 2.0, and americanspecialops, Lilja and several builders give a Lilja barrel.

Its spec table's 10 round magazine belongs to its Mod 7. Copy it into a Mod 5 build and you'll buy the wrong magazine.

The sunset silhouette photo shows an Mk 12

High Caliber Sales captions a widely shared sunset silhouette as a Special Forces soldier with the Mk13. We matched it to Navy photo 070907-N-6477M-170, taken at Rawah, Iraq, in September 2007. Its official caption says MK 12, and a companion frame shows the AR pattern rifle in daylight.

We cover the Mk12 Mod 1 SPR of the same era in its own guide. There's also the Lone Survivor Mk12 build, SEAL sniper kit in 2005.

What the 11.4 pound weight leaves out

The americanspecialops spec block lists 11.4 pounds, and Wikipedia's infobox copies it. Neither says what's included.

The author of the AR15.COM build guide puts his Mod 5 at just over 20 pounds with a loaded magazine. He doesn't list what else is mounted.

What you can buy today and what is unobtainable

Seven of the 15 part slots can still take the issued model, bought new. Seven more need a stand in, and one, the IMUNS, is secondhand only.

Mk13 Mod 5 parts in stock on GPP today

Here's what we list for this rifle, at the lowest in stock price on 27 September 2026.

Our builder can't hold a bolt action rifle, so the one click box at the top loads the scope, rings, laser and can, and the gunsmith work stays with you. No build saved on GPP between 10 December 2025 and 27 September 2026 is named after the Mk13.

Sold elsewhere: the action, extractor and Lilja blank

We don't stock these yet, but you can buy them new.

Secondhand only: AICS 2.0, IMUNS, MARS and the Mk11

We found no new AICS 2.0, IMUNS, MARS rail or Mk11 for sale. Owners trade AICS deployment kits and contract IMUNS rails on AR15.COM and Sniper's Hide, and the Mk11 changes hands on the NFA secondary market.

What a Mk13 Mod 5 clone costs today

RW Snyder Gunsmithing's sold listings are the best price guide we found. It asked $5,000 for a Remington Mod 5 style barreled action with a Lilja barrel and MARS rail, and $4,500 for a Stiller barreled action. A complete Stiller rifle with an original case and stock was $11,000.

On 27 September, the new parts we could price for an early pattern build came to $3,041.19. That's the Remington action, Badger extractor, NXS 5.5-22x56, A108 rings, AI magazine, Harris S-BRM and a box of Federal 190 grain.

The total leaves out the biggest costs, which we won't guess at: the Lilja barrel, an AICS 2.0, a MARS rail, the Mk11, a trigger and your gunsmith's time.

The civilian legal path to a Mk13 Mod 5 clone

The rifle needs no NFA paperwork. Only the can is an NFA item.

A Title I bolt action: only the action is serialized

Nothing on a Mod 5 is a machine gun part, so you have no select fire parts to swap. The barrel runs about 26.5 inches, far past 16, so you need no pinned muzzle device and no SBR paperwork.

The action is the serialized part and ships to your FFL. A surplus AICS kit without a receiver or barrel is just parts under federal law.

Gunsmith work: truing, extractor, chamber and notches

Your gunsmith trues a Remington action and fits the M16 extractor, which owners say a Stiller doesn't need. Then they chamber the Lilja blank in .300 Win Mag at about 26.5 inches, cut the Mk11 latch notches and index pin, and drop the barreled action into the AICS with no bedding.

Owners name Red Bull Armory, RW Snyder Gunsmithing, LongRifles Inc., AJ Brown Arms and Raven Rifles as builders who know the pattern. We have no tie to any of them.

The Mk11 can is the only NFA item

ATF announced on October 9, 2026 that it would stop enforcing approval and registration for suppressors, but your state still has to allow them, and some only allow registered cans. Our guides to the ATF paperwork rule and suppressor paperwork in 2026 cover what changed.

Owners disagree on whether your gunsmith needs the can to cut the notches, so ask before you buy one. You can also skip the can, since the rifle needs no muzzle device.

Sources and photo credits

Where each fact in this guide comes from

Public domain Mod 5 photos and what each shows