Mk13 Mod 7 clone build: the .300 Win Mag that replaced the M40

In April 2018 Marine Corps Times reported that the Corps would spend nearly $4.3 million on 356 Mk13 Mod 7 sniper rifles to replace the M40 series. The rifle came from SOCOM: a Stiller action in an Accuracy International chassis, with a Lilja barrel and, for the Marines, a Nightforce scope.

You can build a close Marine clone today, except for two parts that only turn up in private sales: the Stiller Mk13 action and the AI chassis.

What a Mk13 Mod 7 clone copies

A Mk13 Mod 7 clone copies the .300 Win Mag bolt gun the Marines began fielding in September 2018, or the SOCOM rifle it came from.

You'll spot a Marine rifle by its round Stiller receiver, tan AI folding chassis, bright unfluted barrel, LaRue QD mount with a night sight rail and tan Win Mag can. Decide SOCOM or Marine first. The trigger, muzzle device, scope and mount differ, and the Marine rifle has the better paper trail.

Mk13 Mod 7 parts list: the issued part and what to buy

Here's every slot on the Marine rifle, the SOCOM part where owners say it differed, and what you can buy. We cross checked an enthusiast Mk13 Mod 7 parts list, which names two parts in five slots without saying which unit used which.

Parts from this guide that we stock, laid out overhead. Product photography is supplied by the listed merchants through their affiliate feeds.

Status is ours. Exact is the issued part or its current version, stand in a different product, sold elsewhere a part our feeds carry that we don't list yet, and gone a part nobody sells new. Evidence runs from strong (official photos, records or the maker) to weak (one forum claim).

Mk13 Mod 7 variants: SOCOM and Marine Corps builds

Owners describe two Mod 7s. Raven Rifles splits a first Navy contract from a second USMC one, and a 2025 Sniper's Hide thread splits SOCOM and Marine parts.

The Marine build is the documented one. SOCOM parts come from owners, who put a Schmidt & Bender PM II PSR on the first rifles. Steve Reichert, a former Marine sniper who wrote a Mk13 history in 2018, says they started on XTSP triggers.

Owners say later SOCOM rifles moved to ATACRs and Geissele triggers. For a SOCOM clone, you pick a year as well as a unit.

Mk13 Mod 7 history: from SOCOM to the Marine Corps

Navy gunsmiths began building .300 Win Mag Mk13s for SEAL snipers in the early 1990s, and NSWC Crane later built and supported them. We also cover the Mk12 Mod 0, another NSWC Crane precision rifle.

Why Crane rewrote the Mk13 in 2013

Earlier Mods used reworked Remington 700s in McMillan stocks, then AI's AICS 2.0, with barrels cut for the can from the Mk11 Mod 0, source of the old Mk13 suppressor. Crane began buying Stiller receivers around 2010.

When the AICS and Mk11 contracts lapsed in 2013, Reichert writes, former SEAL sniper Chris Higgins drew up requirements at Crane for a new stock and a Win Mag suppressor. SEAL snipers asked for a two stage trigger too. AI won the stock, SureFire and AAC shared the can award, and the rifle got a new Mod number. Lilja, missing from his account, says it's the SEALs' exclusive Mod 7 barrel supplier.

MARSOC and the SEALs before the fleet

Reichert says MARSOC got the Mod 7 first, since the SEALs still had AICS stocks and Mk11 cans for Mod 5s. An AR15.COM owner says the SEALs went first and about 10 rifles went to MARSOC early. By May 2018 Marine Corps Systems Command called it MARSOC's primary sniper rifle.

The Marine Corps buys 356 to replace the M40A6

The 3rd Battalion, 5th Marines scout sniper platoon carried the Mk13 for more than a year, including a deployment. Then the April 2018 buy made it the Corps' primary sniper rifle, a role the M40 series had held since 1966.

Fielding reached I Marine Expeditionary Force the week of 17 September 2018. Marines.mil put full operational capability in the second quarter of fiscal 2019, a translated programs book in the third. The M40A6 stayed on for training to save Mk13 barrel life, and the Mod 7 served beside the M110 SASS that stayed in the scout sniper kit.

The Stiller action, trigger and AI chassis

Both issued parts you can't buy new are here.

Action: the Stiller Mk13 long action

The Mod 7 uses Stiller Precision's Mk13 long action in .300 Win Mag, a round receiver on the Remington 700 footprint, with an RFID label on Marine rifles.

Raven Rifles says Navy actions are marked Wylie, TX and USMC ones Garland, TX. Nobody else confirms it. We don't list stripped actions, and you won't find an issued Mk13 action new. Owners use a Stiller TAC 30 or TAC 300, and Stiller says the Navy tested five TAC 300s before it won.

Chassis: the AI Mod 7 folding chassis, not an AICS 2.0

The issued chassis is Accuracy International's Mk13 Mod 7: AX family aluminum with a folding, adjustable stock, an AI grip, a KeyMod forend and AICS pattern magazines. The polymer AICS 2.0 belongs to the Mod 2 and Mod 5.

Owners call the color Pale Brown, though AI's name for it is unconfirmed. One AR15.COM member relayed in 2020 that two dealers called AI's commercial version discontinued. You'd substitute an AX or AX AICS, which we don't list, so our cards are lookalikes, not AI parts. Magpul's folding Pro 700L chassis in FDE and KRG's Whiskey-3 Pro fold like the issued chassis.

The Pro 700L takes AICS magazines.

Trigger: Geissele Super MK13, XTSP on early SOCOM rifles

Marine rifles carry Geissele's Super MK13, a two stage the raffle list gives as non adjustable at 3.5 lb. Reichert says SOCOM rifles started on XTSP Mk13 triggers after Remington's X-Mark Pro failed the drop test. A Geissele representative posted in 2019 that its MK13 triggers went to USSOCOM and the Marine Corps.

Neither is sold, and Geissele's Super 700 was out of stock in our feeds.

The TriggerTech R70 is a two stage stand in, and the Timney is a cheaper single stage. A forum user relays Geissele saying its MK13 trigger fits the Mk13 receiver's larger trigger well, so no Remington 700 trigger is a sure fit in a Stiller Mk13 action.

Magazines: eight AICS pattern five rounders

The raffle list gives eight Magpul PMAG 5 AC L Magnum magazines plus one factory AI magazine, and the translated programs book also counts eight five rounders.

Bravo Company, 3rd Reconnaissance Battalion Marines fire Mk13 rifles in gas masks at Camp Hansen, Okinawa, on 17 April 2019. The caption gives no Mod number, but the tan chassis, tan cans and black AICS pattern magazines match the Mod 7. U.S. Marine Corps photo by Lance Cpl. Joshua Sechser, public domain, via DVIDS.

Our exact card is the MAG698, which six merchants in our feeds had in stock on 27 September. The factory AI .300 Win Mag magazine covers the one AI magazine per kit, though no source says which AI model was issued.

The Lilja barrel, muzzle device and ammunition

Your gunsmith does most of the work here.

Barrel: Lilja stainless in the 147 taper, 1 in 10 twist

The barrel is Lilja stainless with a 1:10 twist, unfluted and threaded 5/8-24. Lilja lists taper 147 as the Mod 7 taper: 1.250 inches for 4 inches, then straight to .759 at 28 inches, or .800 at 26.

Finished length is disputed: 25 inches on the raffle list, 26 in three other sources, including a Rock Island rifle from the same collector, Ryan Niederman.

Lilja says it sometimes puts overrun Mod 7 barrels on its Extras list for clone builders, but we don't list them, so our cards are Shilen .30 caliber barrels for your gunsmith to chamber and thread.

The stainless one had no in stock offer on 27 September, neither is taper 147, and the chrome moly one won't look bright.

Muzzle device: SureFire FH762RC or a SOCOM brake

Marine rifles wear SureFire's FH762RC, a four prong 5/8-24 hider that doubles as the suppressor mount. The 2014 AR15.COM list gives SOCOM rifles a SureFire SOCOM brake or an AAC 90T brake. We don't list the FH762RC.

The SF3P has three prongs. The SureFire brake suits a SOCOM build.

Ammunition: 190 and 220 grain match loads

Mk248 Mod 0, a 190 grain load, and Mk248 Mod 1 at 220 grains are the military rounds tied to the Mk13. Reichert wrote in 2018 that Marine snipers were still shooting old A191 190 grain stock.

One AR15.COM poster says the Mod 7 chamber is throated for Mod 1. Nothing official backs that, so have your gunsmith match the throat to your load. Our cards are commercial match loads at the military bullet weights.

Our .300 Win Mag ammo page tracks the price per round.

Mk13 Mod 7 scope and scope mount

The Marine optic stack is documented down to an engraved part number.

Scope rail: the AI 20 MOA Picatinny rail

The raffle list puts the mount on an AI 20 MOA rail, and a 2020 photo shows a chassis colored rail over the receiver. That 20 MOA is why the issued mount is zero MOA.

We don't list the AI rail. Our card is a Seekins one piece 20 MOA base for a Remington 700 long action, out of stock on 27 September. Talley makes Stiller specific bases, so check your action's screw spacing.

Scope: the M571 ATACR for Marines, S&B for early SOCOM

The Marines' M571 is a Nightforce MIL-SPEC ATACR 5-25x56 F1 with the Horus TReMoR3 reticle, per Horus, Marine Corps Times and the raffle list. For SOCOM, owners describe a Schmidt & Bender 5-25x56 PM II PSR first, then ATACR 5-25s, and one says the 7-35 ATACR now.

The first card is the exact commercial scope. Its listing says 65mm, but its merchant links say 5-25x56, and the MIL-SPEC version may differ in turret details. The 7-35 suits a later SOCOM build. We don't list the S&B.

Scope mount: LaRue LT840 QD in zero MOA

A February 2020 official photo shows a 1st Reconnaissance Battalion Mod 7's LaRue mount engraved LT840H-34-0: 34mm, quick detach, zero MOA. The raffle list agrees. LaRue said in 2015 that the LT840-34 had become the Marines' Scout Sniper Day Scope Improved Mount.

A 1st Reconnaissance Battalion team leader fires a Mk13 Mod 7 at Fort Greely, Alaska, on 20 February 2020, before exercise Arctic Edge 2020. The LaRue mount is engraved LT840H-34-0 and the bolt is spiral fluted. U.S. Marine Corps photo by Lance Cpl. Jose Gonzalez, public domain, via DVIDS.

Skip the more common 20 MOA LT840-34-20, since it doesn't belong on a 20 MOA rail. Owners disagree on whether the LT845 was issued, and they put AWP rings on NSW rifles and a LaRue OBR QD on MARSOC ones. We don't list LaRue mounts.

The Unimount is zero MOA per its listing, and an owner names one on an ATACR, maybe on a Mod 5.5. The Leupold Mark IMS is zero MOA but not QD.

Night vision: a clip on sight on the diving board

The mount's short forward rail, the diving board, carries a clip on night sight ahead of the scope. The translated programs book lists AN/PVS-27 compatibility, but which sight units issued is unconfirmed. We don't list the PVS-27 or the QD LT840H-34-STK board owners say later kits used, so our cards are commercial clip on thermals rather than image intensifiers.

Suppressor, bipod, laser and the rest of the kit

The translated programs book lists the rest of each kit: a bipod, eight magazines, a sling, a suppressor, a case and a cleaning kit.

Suppressor: the SureFire SOCOM can or the AAC Mk13

Marine rifles use SureFire's SOCOM762-RC in Dark Earth. The raffle rifle came with a certificate for one, official photos show tan cans, and Crane's 2017 SureFire contract, about $10 million, covered support for Mod 7 brakes and suppressors. AAC's Mk13-SD shared the FMBS suppressor award, but which units carried it isn't established.

SureFire's current version is the RC2, our closest card. The AAC had no in stock offer on 27 September.

Both cans are NFA items. If you can't own one, SureFire's black Suppressor Trainer is a non NFA dummy, but confirm it fits your mount.

Bipod: a Harris swivel bipod on the forend stud

The raffle list gives a Harris BRMS swivel bipod, donated by Harris as the mil spec item, and official photos show Harris style bipods. Harris calls that 6 to 9 inch notched leg model the S-BRM. The enthusiast list adds a LaRue QD adapter no kit list includes.

Our exact card is the S-BRM, and the S-BRMP is the same bipod with a Picatinny mount.

Laser: in a 2021 photo, in no kit list

No Mod 7 kit list names a laser, yet an official August 2021 photo of a 3d Battalion, 2d Marines rifle shows a tan PEQ-15 type module on the forend. You can't read the model.

The enthusiast list names an AN/PEQ-15 and an LA-5, and we found no source for the LA-5. The PEQ-15 goes only to police and the military, so you'd buy its civilian version, the ATPIAL-C. Here are civilian IR lasers compared.

The tan ATPIAL-C had no in stock offer on 27 September. The DBAL-A3 is a black stand in.

Sling and case: VTAC MK2 and a Pelican iM3300

The raffle list gives a VTAC MK2 padded sling, VTAC-MK2-CT-UG, and a Pelican iM3300 Storm case with cut foam, a tool bag, a Mk13 Mod 7 multi tool and cleaning gear. The Pelican 1120 and sterile FDE soft case you'll see in forum posts belong to an XM2010 kit.

Our exact card is that VTAC MK2 in coyote, and the Magpul MS1 is a padded coyote stand in. Our feeds had the iM3300 at two merchants, but we don't list cases yet, and nobody sells the foam or multi tool.

Mk13 Mod 7 vs Mod 5 and the Mk22

The Mod 7 sits between the Mod 5 it replaced and the Mk22 that's replacing it.

What changed from the Mod 5

The Mod 7 swapped the Remington 700 for a Stiller and the AICS 2.0 for an AI aluminum chassis. It traded the old rails for an AI rail, and the Badger IMUNS night sight mount for a rail on the scope mount. Late Mod 5s had Stillers too.

The can changed most. Mod 5 barrels were contoured for the KAC Mk11, and aggregator write ups still say the Mod 7 takes it, but the Mod 7 uses Win Mag cans from SureFire and AAC. If you own a Mod 5 clone, see the AICS stocked Mk13 Mod 5 it replaced.

The Mk22 and the Mod 7s still in service

By March 2020 the Marines had picked Barrett's MRAD, fielded as the Mk22 Mod 0. A 2022 MCSC caption said it would replace all M40A6 and Mod 7 rifles from fiscal 2023, and it reached full operational capability in November 2024. MCSC noted older rifles needed intermediate maintenance for repairs, and a condemned barrel left them unusable.

A Maritime Raid Force Marine with Littoral Combat Force-24 chambers a round in a suppressed Mk13 Mod 7 at Camp Santiago, Puerto Rico, on 1 June 2026, well after the Mk22 reached full operational capability. U.S. Marine Corps photo, DVIDS byline Cpl. Daniel Garcia, public domain, via DVIDS.

You'll read that the Mod 7 retired in 2021. Captions still name it with 3d Littoral Combat Team scouts in February 2024 and a Maritime Raid Force in June 2026, though captions can misidentify rifles.

What the internet gets wrong about the Mk13 Mod 7

Clone lists, product pages and Wikipedia repeat the same errors, so here's what the records show.

Chris Kyle never carried a Mod 7

Search for Chris Kyle's .300 Win Mag and Mod 7 pages come up, Lilja's first in one search we ran. Kyle left the Navy in 2009, years before the Mod 7 took shape.

Wikipedia's Kyle article calls his rifle a McMillan stocked Remington 700 later classified Mk13 Mod 1, while its Mk 13 article files him under the Mod 0. Our guide to the Mk13 Mod 0 Chris Kyle's rifle belongs to covers it.

Wikipedia's infobox numbers are not Mod 7 numbers

Wikipedia's Mk 13 article showed up in every Mk13 search we checked. Its infobox's 673 mm barrel is Reichert's figure for most Mod 0 barrels, its magazine is labeled for the Mod 5, and its lead describes a Remington 700 in an AICS 2.0.

Marine Corps Times slipped too, captioning the ATACR as picked for "the Mk 17 Mod 3", a SCAR-H.

A SEAL Team Six spec with no source behind it

Charlie's Custom Clones' Mod 7 page calls it SEAL Team Six's standard sniper rifle, on a Stiller TAC 300 with a Schneider barrel, TriggerTech trigger and AAC Cyclone pattern brake. We found no source for the unit claim, and the documented parts are Lilja, Stiller Mk13, Geissele or XTSP and SureFire.

What you can buy today and what is unobtainable

We carry 13 of the 17 slots, one more sits in our merchant feeds, and three issued parts are gone.

Mk13 Mod 7 parts in stock on GPP today

Here's what we list for a Marine pattern build, at the lowest in stock prices on 27 September 2026.

Our builder can't hold a bolt action rifle, so the one click box at the top loads the scope, mount, muzzle device, can and laser, and the gunsmith work stays with you. In the 90 days to 27 September 2026, visitors searched our catalog for "bolt action" 13 times, and six searches came back empty under an upper receiver filter.

Sold elsewhere: the Pelican iM3300 case

Our merchant feeds had one kit part in stock on 27 September that we don't list yet.

Gone: the Stiller Mk13 action and the AI Mod 7 chassis

Nobody sells these new: the Stiller Mk13 action, the AI Mod 7 chassis, the Super MK13 and XTSP triggers, the original Dark Earth SOCOM762-RC, the AN/PVS-27 and Mk248 ammunition. Issued actions and chassis surface only in private sales and completed kits.

Our feeds had no Stiller TAC 30, TAC 300 or AI AX either. They did carry Remington 700 footprint magnum actions from makers like Bergara, Defiance and Kelbly's, and folding chassis from Magpul, KRG and MDT.

Complete clones for sale, and how close they are

If you'd rather buy one finished, Charlie's Custom Clones sells complete Mod 7 clones and credits the builds to Chris Higgins at Red Bull Armory. Its TAC 300, Schneider barrel, TriggerTech trigger and AAC brake aren't the documented parts.

Rock Island Auction listed a cased, Mod 7 configured Stiller from the Niederman collection for its August 2025 sale, also credited to Higgins, with a Wylie, TX action, XTSP trigger and FH762RC. It sat in an early FDE AI AX chassis.

What a Mk13 Mod 7 clone costs today

On 27 September 2026 the in stock parts in our table came to $5,894.57: the ATACR, the RC2, a TriggerTech, an SF3P, a box of Federal, a Harris S-BRM, eight PMAGs and the VTAC. The iM3300 sold elsewhere added $357.95.

We can't price the biggest costs, so we don't estimate them: the action, chassis, Lilja barrel, LaRue mount, AI rail and your gunsmith's time.

The civilian legal path to a Mk13 Mod 7 clone

The law is the easy part of this clone. Only the suppressor is an NFA item.

The rifle itself is an ordinary Title I rifle

The Mod 7 is a bolt action with a 25 or 26 inch barrel. With no auto sear, there's no select fire part to swap, and a barrel that long needs no pinned muzzle device or SBR paperwork. Hiders and brakes aren't NFA items, but check your state's muzzle device rules. Your action ships to an FFL.

Check your state before you buy the suppressor

ATF announced on October 9, 2026 that it would stop enforcing Form 4 approval for suppressors like a SOCOM762-RC2 or AAC Mk13-SD, but your state still has to allow them. Our guides to the ATF paperwork rule and suppressor paperwork in 2026 cover the process.

Sources and photo credits

Where each fact in this guide comes from

Official Mod 7 photos and their credits

Two of the linked photos carry conflicting credits, so we give both names.