M110 SASS clone build: the Army's KAC sniper rifle, part by part

In April 2007, Task Force Fury snipers at FOB Salerno, Afghanistan, became the first soldiers in a combat zone to get a new Knight's Armament rifle, then called the XM110. Marines were still firing it in February 2026.

You can build a close M110 clone today, but the KAC core is out of stock or out of production. Here's every slot, what was issued and what you can buy.

What an M110 SASS clone copies

An M110 SASS clone copies a 20 inch KAC rifle built around a quick detach suppressor. PEO Soldier called the M110 the first Army weapon system to integrate one.

M110 specs from PEO Soldier and KAC

The cards above come from PEO Soldier and KAC. PEO adds a muzzle velocity of 2,571 ft/s, and KAC's barrel is chromoly with 5R rifling.

Weights and lengths vary because each source measured a different setup. Treat KAC's 46.75 inches, stock retracted, as a conflict: PEO gives 40.5 inches unsuppressed and 46.5 suppressed, stock compressed.

The five parts that separate an M110 from an SR-25

People call the M110 an SR-25 or a Mk11 in Army markings. Your clone needs the five parts that set it apart:

• A KAC URX II rifle length forend with a built in folding front sight
• A fixed stock with a length of pull knob and QD sling sockets
• The M110 flash hider that its QD suppressor mounts on
• A KAC one piece 30 mm scope mount
• A bolt catch on both sides of the lower

An Army M110 photographed by the Idaho Army National Guard on 3 October 2018: the URX II forend (P/N 24124 on its marking), a tan scope in a one piece mount, a KAC folding rear sight, the fixed stock with its length of pull knob, a Harris type bipod and the M110 suppressor. The lower is marked U.S. M110 and KNIGHT'S ARMAMENT CO. Photo by Thomas Alvarez, Idaho Army National Guard, public domain, via Wikimedia Commons.

M110 SASS parts list: the issued part and what to buy

Here's every slot in the order of one enthusiast M110 parts list, plus magazines and finish. We checked that list against Army and KAC records, and each part section notes where they differ.

Parts from this guide that we list, laid out overhead. The KAC lower, SR-25A2 upper kit, URX 6 rail, taupe front sight and 200 to 600 meter rear sight had no in stock offer on 27 September 2026. Product photography is supplied by the listed merchants through their affiliate feeds, and some photos show a different color or the whole rifle.

Evidence grades the source. Strong is an Army or KAC document or a legible marking in a dated photo, moderate is photos alone, and weak is one enthusiast source.

Exact is the issued part and equivalent a stand in doing the same job. Hunt used means only the used market has it, missing means we don't stock it yet, and unobtainable means no feed we read carries it.

M110 history: from the XM110 to Army and Marine snipers

The rifle reached a combat zone in April 2007, a year and a half after KAC won the contract. Army photos from 2024 still show it in use, nearly eight years after the Army picked HK's rifle to replace it.

Why the Army wanted a semi auto sniper rifle

Iraq pushed Army snipers into short, fast urban fights where the five round, bolt action M24 was slow to reload, so many teams carried an M4 as a second weapon. The Army bought a commercial, non developmental design through the Soldier Enhancement Program.

From XM110 to M110: the 2005 win and 2007 release

KAC's rifle won on 28 September 2005 as the XM110, and by June 2006 PEO Soldier planned to field 4,492. Task Force Fury (4th Brigade Combat Team, 82nd Airborne Division) got the first ones in a combat zone in April 2007.

Full materiel release followed that August. Fort Polk snipers got M110s in mid November 2007, the first fielding before a deployment.

Meant to replace the M24, it ended up beside it

PEO Soldier's 2006 article called the XM110 the M24's replacement. The Army kept buying M24s until 2010 and then rebuilt them as the .300 Winchester Magnum M2010, so the two rifles served as a pair.

Who carried the M110: Army, Marines and SOCOM

After the first Army units, photos show it with the 173rd Airborne Brigade, the 10th Mountain Division and infantry and cavalry units.

The Marine Corps bought 803 on the Army contract in June 2010 and fielded them to scout snipers from January 2011, replacing the M39 and Mk11 Mod 1 and backing up the M40A5. For the bolt gun that later replaced the M40, see our Mk13 Mod 7 clone build.

In October 2019 NSWC Crane moved to buy KAC 6.5 Creedmoor upper conversions for SOCOM's M110K1s. We haven't verified Wikipedia's list of foreign users.

M110 vs Mk11, M110A1, M110A2 and M110A3

The Mk11, M110A2 and M110A3 are Knight's Armament rifles, and the M110A1 isn't. If you'd rather build in 5.56, see the Army's 5.56 SDM-R or the 5.56 Mk12 Mod 1 with a KAC rail.

M110 vs Mk11 Mod 0, and when the changes came

The M110 grew out of the Mk11 Mod 0, the M110's SOCOM predecessor. It swapped the Mk11's free floated RAS for the URX II and added the knob stock, the flash hider and QD can, and the one piece mount.

Wikipedia credits those changes to a 2007 user group, but a June 2006 PEO Soldier article already shows the XM110 with a URX style forend and a suppressor. Only the knob, QD sockets, double sided bolt catch and front sight lock button tie firmly to the XM110 to M110 change.

M110A1: the HK CSASS, not an upgraded M110

Heckler & Koch won the Army's Compact Semi-Automatic Sniper System contract on 31 March 2016 with a modified G28, an HK417 family rifle, for up to 3,643 rifles. The Army called it the M110A1, and by 2020 HK was delivering it as the Squad Designated Marksman Rifle. Its parts won't help your KAC clone.

M110A2 and M110A3: KAC's own successors

KAC's M110A2, already in its 2020 catalog, has a URX 4 M-LOK rail, a QDC three prong flash hider and a collapsible stock. Its twist went from 1 in 11 in that catalog to 1 in 10 on KAC's current page.

The M110A3 is KAC's 22 inch 6.5 Creedmoor rifle. SOCOM's 2019 6.5 Creedmoor upgrade was for its M110K1s, so it belongs with the 16 inch M110K1 carbine.

KAC's QDC flash hider is the one documented M110A2 part we have in stock. Ours is threaded 5/8-24 and the A2's thread isn't documented, so match it to your barrel.

M110 variants: Army and Marine rifles, 2007 to 2026

The enthusiast list gives five scopes and two stocks without saying which service or year used them. Here's what dated records show.

Army rifles: Mark 5HD selected in 2020, B5 stock kit in 2022

The original Army rifle carried a tan Leupold Mark 4 3.5-10x40 in KAC's one piece mount. In 2020 Leupold's Mark 5HD 3.6-18x44, in FDE with the Army's Mil-Grid reticle and a Mark IMS mount, was selected for it.

Selected isn't replaced. Our hero photo, from February 2024, shows a 2nd Cavalry Regiment M110 still wearing a tan 1/2 MOA scope in the KAC mount. In June 2022 the Army added the B5 Collapsible Precision Stock to its sniper accessory kit for the M110.

The IMS and B5 are the issued products, in versions the Army didn't specify. Leupold's Mil-Grid scope isn't confirmed for civilian sale, so our PR2-MIL Mark 5HD is an equivalent. The IMS needs a 35 mm tube, and the B5 a carbine receiver extension.

Marine rifles: Premier in 2011, PM II and PRS in 2024 photos

Marine rifles carried a Premier Reticles scope from 2011, in separate rings in a 2011 photo. The enthusiast list names a Heritage 3.5-15x50 Gen I, and we couldn't confirm it.

Sgt. Maj. Micheal P. Barrett, the 17th Sergeant Major of the Marine Corps, fires an M110 at Quantico, Virginia, on 26 July 2011. The Marine Corps caption says the rifle is equipped with a Premier Reticles optical sight; the black scope, marked PREMIER, sits in separate rings. U.S. Marine Corps photo by Lance Cpl. Cody A. Fodale, public domain, via Wikimedia Commons.

The Marines' FY2021 budget request added an M110 product improvement program without naming the parts it changes. A July 2024 Force Recon rifle has a Magpul PRS, a Schmidt & Bender PM II and a polymer magazine, while a February 2026 rifle keeps the fixed stock under a PM II.

A Marine of 3d Force Reconnaissance Company, 4th Marine Division, trains with the M110 at Panzer Kaserne, Germany, on 18 July 2024. This rifle wears a Magpul PRS stock, a Schmidt & Bender PM II scope in separate rings and a polymer magazine, and rests on a tripod with its bipod folded. U.S. Marine Corps photo by Lance Cpl. Garrett Gillespie, public domain, via Wikimedia Commons.

Our PRS and PM II are equivalents. We couldn't identify the rifle's PRS generation, and the Marine scopes' magnification isn't legible, so our 5-25x56 PM II matches the maker and model line only. We don't stock a Premier yet.

The lower receiver group

Your lower will be a commercial KAC receiver, out of stock in our feeds today, and the issued stock is a used market hunt.

Lower receiver: KAC SR-25 in place of the marked M110

Issued lowers are marked U.S. M110 and KNIGHT'S ARMAMENT CO., with ambidextrous controls. You can't buy those marks, so the commercial KAC SR-25 lower is your faithful equivalent.

It has two offers and none in stock, and the listing doesn't confirm the second bolt catch. The CMMG is a budget AR-10 lower for the look alike route, not confirmed with a KAC upper.

Trigger and guard: KAC two stage, plain GI guard

The issued trigger is KAC's two stage match trigger, semi only, and we couldn't find it sold alone. Geissele's SSA-E, the trigger in Geissele's proposed M110 upgrade, is the closest equivalent in stock.

The G2S is the budget pick. Both are small pin AR triggers, so check your lower's pin size. A 2013 Marine photo shows a plain standard guard, matching the enthusiast list's GI listing. Our USGI guard is an AR-15 part we couldn't confirm on a KAC SR-25 lower, so check the fit before you order.

Stock: fixed M110 A2 profile with a length of pull knob

The issued stock is a fixed A2 profile in FDE with a notched knob for length of pull and a flush QD socket on each side. Nobody we found sells it.

Both are equivalents without the knob or sockets, and the Magpul isn't an A2 profile. We haven't matched the M110 receiver extension, buffer and spring on NS Armory's checklist either.

Grip: tan A2 profile, maker not on record

The 2018 studio photos show a tan A2 grip with no maker mark, other photos a black one, and the enthusiast list gives a KAC taupe A2 or an Ergo. Both cards match the description, not a documented part.

The upper receiver group

A clone on today's KAC parts drifts from the 2007 rifle here, because KAC changed its barrel.

Upper receiver: KAC SR-25 flat top, stripped or A2 kit

The issued upper is a KAC flat top in FDE. KAC's 20 inch SR-25 A2 upper kit, PN 121471, is your civilian equivalent. Both of our listings are out of stock, and the assembled one is black. We don't list a stripped KAC upper.

Barrel: 20 inch 1 in 11 on issue, 1 in 10 on today's KAC uppers

The issued barrel is KAC's 20 inch chromoly with 5R rifling and a 1 in 11 twist, optimized for M118LR. KAC's current A2 upper uses a 1 in 10 barrel, the M110A2 spec, and KAC doesn't sell the M110 barrel alone in our feeds.

Criterion's barrels match the length and twist, but one feed lists a 5/8-24 thread where the M110 flash hider needs 3/4x24, and we haven't confirmed them in a KAC upper.

Gas block: KAC SR-25 block with the suppressor latch

The M110 can latches onto KAC's SR-25 gas block, so the block is half of your suppressor mount. No document gives the gas length, though NS Armory's checklist calls for a rifle length tube. We found the block in no feed and couldn't confirm current KAC blocks keep the latch.

Muzzle device: the M110 flash hider, KAC 25877, 3/4x24

KAC's M110 flash hider is a slotted birdcage, 2.6 inches and 3.4 oz, with a four piece shim kit, and only KAC gives its thread. We don't carry it, so you'll buy from KAC or used.

The LBE birdcage is a budget look alike. It won't take the M110 can, and its listing doesn't state the thread.

Bolt carrier and charging handle: SR-25 parts only

KAC calls its E2 bolt backward compatible with M110 carriers. That points to a legacy SR-25 bolt on issued rifles, though no document names it, and KAC's E2 Mod 1 carrier kit sits unmatched in two feeds at $848.16.

Photos show a plain single latch handle. Our guide covers other SR-25 compatible charging handles.

The LBE and Radian handles are equivalents, though only the Radian is listed for the SR-25. The Faxon is a budget AR-10 carrier we haven't confirmed in a KAC upper.

The M110 handguard, iron sights and scope

The URX II rail gives the M110 its look, and you'll struggle to find one.

Handguard: KAC URX II 7.62 with its folding front sight

The 2018 Army rifle's forend is marked URX II 7.62, P/N 24124, and a 2024 Marine rifle shows the same URX II marking. It free floats the barrel under full length rails with a folding front sight built in. The enthusiast list shows that sight as N/A, but it's on the rail.

The URX II isn't in KAC's 2020 catalog or any feed we read, so you're hunting a used one. KAC's URX 6 is the current stand in, unconfirmed on an M110 era barrel nut, and Sons of Liberty lists its M89H for the SR-25.

Both are stand ins. Without the built in sight you'll want KAC's taupe folding front sight, or the budget Magpul MBUS.

Rear sight: KAC folding, full size knob or micro

Sniper Central describes a folding match peep rear sight that stays mounted under the scope, model undocumented. The enthusiast list names KAC's full size 200 to 600 meter sight, and the big knob in a 2013 Marine photo leans that way.

Both are equivalents. The one that looks full size by its name is out of stock, and our only in stock KAC rear sight is a micro. KAC's 600 meter folding sights also sit on the KAC era M4A1 Block I clone.

Optic: Leupold Mark 4 LR/T 3.5-10x40 in tan

The Army's scope was a tan Leupold Mark 4 LR/T 3.5-10x40 with an illuminated mil reticle, and Sniper Central adds a TMR and M2 turrets with an M118LR dial. It's discontinued.

Our Mark 4 LR/T 3.5-10x40 has M1 turrets and an illuminated mil dot, its listing doesn't give the color, and its one offer is out of stock. The Mark 4HD 2.5-10x42 with an illuminated TMR is the current production equivalent, in black.

Scope mount: KAC one piece 30 mm, hard to find new

KAC's one piece 30 mm mount, knight logo and all, is in no feed and looks out of production.

Geissele's Super Precision in DDC is the closest tan equivalent, and the American Defense Delta QD the budget pick. No document or photo we found confirms the enthusiast list's Badger Ordnance 306-76 or 306-54.

Night sight and laser: PVS-26 issued, no laser on record

The AN/PVS-26 clip on night sight mounted ahead of the scope and came with the rifle at Fort Polk in 2007. PEO lists no laser, and nothing we found ties the enthusiast list's AN/PEQ-15 or LA-5 to the M110.

If you want one anyway, the civilian ATPIAL-C is the usual look alike, and none of our merchants has one in stock.

M110 suppressor, bipod and issued kit

The Army issued the M110 as a system, with the can, a bipod, magazines, a spotting scope and cases.

Suppressor: the KAC M110 QD can and what it needs to mount

The issued can is KAC's M110 QD suppressor, PN 24611, in stainless steel. KAC lists it at 14 inches and 32.0 oz, and it only mounts with the M110 flash hider and the gate latch gas block.

That's the exact issued can, and none of its three offers is in stock. It's an NFA item, covered below.

Bipod: Harris swivel type on a KAC rail adapter

Photos from 2011 to 2026 show a Harris type swivel bipod on a KAC rail adapter, NSN 1005-01-468-0350, but the Harris model isn't documented. The enthusiast list names a BRM-S and a KMW Pod-Loc.

The Harris S-BRM, the enthusiast list's pick, is an equivalent. KAC's current mount for Harris S series bipods is out of stock, so the Midwest QD adapter stands in for it. It isn't the issued adapter, and the KMW Pod-Loc we list is out of stock.

Magazines, the M151 spotting scope and cases

KAC sells 10 and 20 round SR-25 magazines, and we list its steel ones, both out of stock. The 2024 Marine rifle wears a PMAG style 20 rounder instead, and Magpul's 20 and 10 round LR/SR PMAGs are in stock with us.

The spotter's M151 is a Leupold 12-40x60 with a mil dot reticle. Our listings carry other reticles, and a TMR version is in stock in several feeds at $1,999.99, not matched yet. With its cases, the system weighed about 70 lb.

Finish: flat dark earth on rifle, rail and can

KAC coated the receivers, rail, stock and can in flat dark earth, while the Marines' earlier Mk11 Mod 1s were black. Our KAC listings are black, so you'll want to refinish them, as NS Armory does in KAC taupe.

What you can buy today and what is unobtainable

We checked every slot against our merchant feeds on 27 September 2026, and the KAC core is the problem.

M110 parts in stock on GPP today

You can order the triggers, a GI trigger guard, stocks, grips, Criterion barrels, Leupold scopes and spotting scopes, a PM II, Mark IMS and Geissele mounts, a KAC micro rear sight, the Harris S-BRM and QD adapters, Magpul PMAGs and the M110A2 QDC flash hider today.

Listed but out of stock: KAC lower, uppers and the can

The KAC SR-25 lower, both SR-25 A2 20 inch uppers, the M110 can, the URX 6 rail, the Mark 4 LR/T, KAC's magazines and Harris mount, the 200 to 600 meter micro rear sight and every KAC front sight we list had no in stock offer.

Not in any feed: URX II, M110 stock, flash hider, gas block

No feed we read carries the URX II, the issued stock, the M110 flash hider, the gate latch gas block, a KAC scope mount or a Premier scope. KAC's E2 Mod 1 carrier kit and the TMR spotting scope are in feeds we haven't matched, and we'll add cards as we do.

What an M110 SASS clone costs today

We priced each slot that has an in stock stand in at its cheapest offer on 27 September 2026. Card prices are live, so expect drift.

That total skips magazines, plus the receivers, rail, gas block, flash hider and can, since none of those was in stock. It also skips a barrel, because the KAC upper you'd buy comes with one. GPP builders who picked the KAC SR-25 lower, SR-25A2 upper kit and M110 can between 31 January and 27 September 2026 saw medians of $1,528.31, $3,283.20 and $2,260.83, from 43, 9 and 4 priced adds.

How to build an M110 clone: three routes

Each route trades money against how close you get.

Convert a KAC SR-25 A2 rifle or upper

Start on KAC receivers: an SR-25 lower and 20 inch SR-25 A2 upper, or KAC's complete SR-25 A2 rifle (listed, out of stock). Then swap in the URX II, flash hider, gas block, fixed stock, one piece mount and FDE finish. The A2 upper's 1 in 10 barrel makes it an M110A2 underneath unless you replace it, so check its thread before you buy the flash hider.

Clone shops, conversion services and used rifles

NS Armory converts an SR-25 for $2,000.00 in labor, parts extra, and publishes its parts checklist. BG Defense's "M110 clone" is an 18 inch build on non KAC parts.

Used KAC based clones turn up in classifieds and on GunBroker, and one Oklahoma Shooters listing with a government marked Mark 4 asked for offers from $8k. KAC's 110 limited edition sets carry an Export Version title and an ITAR statement, so don't count on buying one.

A budget look alike on AR-10 pattern parts

For the look on a budget, use the AR-10 pattern cards above: the CMMG lower, a Criterion barrel and the LBE birdcage, plus a budget AR-10 quad rail such as ZEV's. KAC rails and gas blocks are made for KAC parts, so check fitment before you mix. Our AR-15 vs AR-10 guide covers what carries over between the two sizes. A look alike can't mount the M110 can.

What GPP builders pair with a KAC SR-25 A2 upper

None of the named carts saved on GPP between 10 December 2025 and 27 September 2026 refers to the M110, SASS or SR-25. The parts tell more.

Ten builders put a KAC SR-25A2 20 inch upper in a cart between 15 April and 8 September 2026. Seven paired it with the KAC lower, and two with AR-15 lowers that can't take it.

None of the ten holds a Leupold, an A2 fixed stock, a PRS or a B5, and their top charging handles are AR-15 parts that don't fit an SR-25. None counts as a whole rifle by our filter, because a complete upper has no separate barrel line.

What the internet gets wrong about the M110

Several M110 errors start on Wikipedia and spread to seller pages. Here's what people call it, and what the records show.

First combat issue: April 2007, not April 2008

If you've read April 2008, that's Wikipedia's date for Task Force Fury's first combat zone issue, and BG Defense repeats the year. The Army News Service story is dated 23 April 2007 and names the XM110.

M110 weight: why sources give 13.8 to 17.3 pounds

Each figure weighs a different setup, so check which one a source means before you compare your clone. KAC's 13.84 lb is the rifle as shown without a magazine, PEO's 15.3 lb is combat ready with scope, bipod and a loaded 20 round magazine, and 17.3 lb adds the suppressor. PEO's 2021 page says 15.7 lb empty.

The Marines chose an M110 upgrade over CSASS

The Marine Corps budgeted 116 CSASS rifles in 2018 to replace the M110. Its FY2021 request swapped CSASS for an M110 product improvement program: 270 units in FY2020 and 184 in FY2021 at $8,393 each.

Nightforce and Mark 4 6.5-20x50: no issue record

The enthusiast list gives a Leupold Mark 4 6.5-20x50 M5A2 and a Nightforce ATACR 5-25x56 F1, and we found no issue record for either. If you want a documented scope, pick the Mark 4 3.5-10x40, a Premier, the Mark 5HD or a PM II.

The 2011 reliability claims and the Army's reply

In April 2011 Kit Up quoted an industry source saying about half of a unit's M110s were being cannibalized for parts. Four days later PM Soldier Weapons said an early trigger problem was fixed, no bolts were cracking and the 173rd Airborne Brigade rated it 100 percent. Treat both as claims.

The civilian legal path to an M110 clone

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

Title I rifle: 20 inches, semi auto, no NFA forms

The M110 is semi auto only, so you've got no auto sear parts to swap, and a 20 inch barrel keeps you clear of short barreled rifle rules. Only KAC's later 14.5 inch uppers would need a pinned and welded muzzle device to 16 inches, or an SBR build.

Buying the M110 can: still an NFA item

The KAC M110 suppressor is an NFA item, but ATF announced on October 9, 2026 that it would stop enforcing approval and registration for suppressors. A dealer still runs a Form 4473, and some states ban cans or only allow registered ones. We don't quote fees: see current NFA paperwork for a suppressor and what changed for suppressor buyers. Buy the flash hider and gas block first, or the can has nothing to mount to.

Military only parts and their civilian stand ins

The AN/PVS-26 and AN/PEQ-15 are military items, so use a commercial clip on night sight and the civilian ATPIAL-C, or skip them. Some PEQ-15 listings in our feeds are law enforcement only, and we won't offer them.

State law: suppressors, flash hiders and magazines

Some states restrict suppressors, flash hiders or magazines over 10 rounds, and the issued rifle has all three. Check your state before you order.

Sources and photo credits

We cross checked one enthusiast M110 parts list against these records and used it as a checklist. Where a pick rests on it alone, the text says so.

Primary documents: PEO Soldier, KAC and Army News

Army, Marine Corps and KAC documents come first, then the press and enthusiast pages.

Reference photos by year, service and configuration

We host public domain originals only.

More public domain photos, by year: the 2018 rifle's muzzle end, a 2013 Marine night shoot, an unsuppressed 2016 M110, a field painted 2018 M110 and the 2026 FASTCENT rifle.