Soldiers of Apache Troop, 1st Squadron, 2nd Cavalry Regiment fire the M240B with an in-line optic during qualification at Grafenwoehr Training Area, Germany, 9 June 2026. US Army photo by Sgt. Scyrrus Corregidor, via the Defense Visual Information Distribution Service (DVIDS), public domain. The appearance of US Department of Defense visual information in this article does not imply or constitute DoD endorsement.

FN MAG Tactical with Long Rail: New Optics for the Jimpy as Britain Buys Ten More Years and America Prices a Successor

Technical Summary

FN Herstal announced the FN MAG Tactical with Long Rail on 21 May 2026, the newest variant of the 7.62×51 mm general purpose machine gun (GPMG) that serves 90 nations as the MAG, the US M240 and the British L7A2. The headline change is an 11-inch monolithic Picatinny rail giving roughly 14 inches of usable space for in-line day, night or thermal optics while the original 200 to 800 m iron sights remain usable beneath. Around the rail sit three supporting changes: a feed-cover retention mechanism that holds the cover open under optics of up to 2.5 kg and stops its travel at 62 degrees to protect a forward lens, a longer articulated carrying handle that allows a hot barrel change with full-length optics fitted, and a telescopic buttstock with three length and six cheek-rest positions. FN offers the package on new-build weapons or as a conversion kit that the company states a unit armourer can fit in minutes with basic tools. The variant makes its public debut at Eurosatory in Paris from 15 to 19 June.

The launch lands in a crowded fortnight for the MAG family. A UK Ministry of Defence (MoD) transparency notice published on 5 June 2026 set out the intent to award Heckler & Koch (UK) Ltd a ten-year, roughly £70 million sole-source contract to supply L7A2 GPMGs and ancillaries to June 2036. In Washington, the US Army's Fiscal Year 2026 budget request seeds a Future Medium Machine Gun (FMMG) effort, reported at around $3.6 billion across development and acquisition, to find the M240's eventual replacement. FN meanwhile sells both sides of the argument: the Long Rail kit extends the installed base, while its 6.3 kg EVOLYS ultralight machine gun is pitched as the clean-sheet alternative and is reported to be entering European service.

Only H&K UK therefore has the technical documentation to continue to supply the GPMG System in the L7A2 configuration. UK MoD transparency notice, 5 June 2026, quoted by UK Defence Journal

The Family in Service: L7A2 and M240

The MAG (Mitrailleuse d'Appui Général) is a gas-operated, open-bolt, belt-fed design firing 7.62×51 mm NATO (North Atlantic Treaty Organisation) ammunition from disintegrating link. FN puts cumulative production in the hundreds of thousands of weapons. Britain adopted it in the early 1960s as the L7, and the current L7A2, known to generations of British soldiers as the Jimpy, remains the army's standard medium machine gun. Official British Army data lists a weight of 13.85 kg with a 50-round belt, a 1,230 mm overall length, a 629 mm barrel, a muzzle velocity of 838 m/s and a cyclic rate of 750 rounds per minute. In the light role on its bipod the L7A2 is effective to 800 m. In the sustained fire (SF) role, tripod-mounted with the C2 optical sight and a two-man crew in battalion machine gun platoons, it engages to 1,800 m. Variants arm most British Army vehicles and several helicopter fleets.

The United States adopted the MAG from 1977 as a coaxial tank gun and extended it to the dismounted role in the late 1990s as the M240B, built by FN America in Columbia, South Carolina. The M240B weighs 12.5 kg; the M240L variant cuts that to about 10.1 kg, an 18 per cent reduction, through a titanium receiver. The type retains its place even as US small arms modernise around it. The 6.8×51 mm M250, type-classified in May 2025, replaces the 5.56 mm M249 at squad level but not the M240, and the US Army placed a further M240L order with FN America as recently as July 2025. The FMMG request is the first funded step towards an actual M240 successor, and Fiscal Year 2025 money was used to test whether the M250 could stand in for the medium gun in the interim.

What the Long Rail Actually Fixes

Clip-on night and thermal sights are now standard issue ahead of rifles' day optics, and recent operational feedback, FN says, demanded the same stacked arrangement on belt-fed guns. The short feed-cover rail of a standard MAG cannot hold two in-line optics with correct eye relief. Simply bolting on a longer rail creates four follow-on problems, and the engineering interest of this variant is that each one is addressed. A rail-mounted sight makes the feed cover heavy, so the FN AUTO-LOCK mechanism holds it open during loading and clearing rather than leaving the gunner to support 2.5 kg of glass with one hand. A fully raised cover would strike a forward-mounted lens against the weapon, so cover travel now stops at 62 degrees. A long optic blocks the standard carrying handle and with it the rapid barrel change that sustained fire depends on, so the handle is lengthened and articulated. Differing eye relief and sight heights across optics require an adjustable firing position, hence the new buttstock. A revised feed-cover latch, the FN SIDE-CLICK, opens from either side with one hand.

FN states the configuration is fully qualified, supported by three pending patents, compatible with its SMARTCORE shot counter, and applicable across MAG, M240 and L7A2 configurations provided the feed cover carries an integrated rail; older plain covers must be exchanged. The company's own guidance is that converting in-service weapons will usually be more cost-effective than buying new, except for guns that are, in its words, very old or worn. Christophe Soleil, FN's Vice President Small Arms, framed the variant as maintaining the weapon's original performance in a configuration supported entirely by FN as original designer and manufacturer. Official imagery is published on FN's product page; the company's demonstration video is embedded below.

Official FN Herstal demonstration of the FN MAG Tactical with Long Rail, embedded from the company's YouTube channel. Video content © FN Herstal.

Succession Planning on Both Sides of the Atlantic

The British contract is the more revealing document. The buyer is the Dismounted Close Combat Team at Defence Equipment and Support (DE&S), the value is around £70 million including VAT, signature is expected no earlier than 29 June 2026, and the award is direct, justified under a single-supplier provision of the Procurement Act 2023. The justification rests on configuration history: H&K performed the L7A2 Mid-Life Improvement in 2007, creating what the notice calls a materially different technical baseline incorporating safety-critical modifications. The result is that a German-owned Nottingham SME, not FN, holds the technical documentation for Britain's version of FN's gun. The British Army still lists Manroy Engineering, now FN Herstal's UK subsidiary, as the L7A2's manufacturer, which illustrates how far design authority has migrated across the fleet's six decades. Reporting based on parliamentary answers puts the L7A2's planned withdrawal at 2035, with a light-role replacement studied under Project Cairns, yet no public requirement or request for information has been issued.

The American position is similar in substance: pay to keep the M240 credible while pricing its replacement. Continued M240L production sits alongside the FMMG request, and the calibre question is open. The 6.8×51 mm round now fielded at squad level offers one path; trade reporting on the FMMG notes the US Army has not yet committed to a calibre, a weight target or a schedule. FN's commercial logic covers every outcome, because its 7.62×51 mm portfolio now spans three weight classes. The MAG anchors the top tier. The middle tier is the FN MINIMI 7.62 Mk3 light machine gun, listed in FN's technical data at about 8.8 kg with a 422 mm barrel and a cyclic rate of around 800 rounds per minute, offered in Standard, Para and Tactical configurations with a 5.56 mm conversion kit. FN fitted a long-rail feed cover to the MINIMI 7.62 Mk3 before the Tactical with Long Rail brought the same concept to the GPMG. The bottom tier is the EVOLYS, with its patented lateral feed, full and semi-automatic capability and roughly half the M240B's mass. If medium machine gun budgets stay with the installed base, the Long Rail kit captures them; if they migrate to a lighter gun, the MINIMI Mk3 and EVOLYS bracket the requirement, and both are obvious candidates for light-role replacements of the Project Cairns type. Trade reporting puts a Belgian intent at more than 3,500 EVOLYS weapons split between calibres, with French service entry reported and an Italian Army evaluation by the 4th Alpini Paratroopers Regiment underway; none of this has been confirmed by the governments concerned.

Personnel and Safety Considerations

For WOME (Weapons, Ordnance, Munitions and Explosives) practitioners the kit raises configuration-control questions before it raises tactical ones. The UK case is the sharpest example: the L7A2 baseline is defined by safety-critical modifications whose documentation sits with H&K UK, so fitting any third-party conversion to British guns would require design-authority assessment and re-qualification, however straightforward the armourer-level installation appears. Any force adopting the kit should re-zero converted weapons and revalidate boresight before SF-role employment at the 1,800 m end of the envelope, audit in-service night and thermal sights against the stated 2.5 kg cover-retention rating, and amend barrel-change drills to reflect the articulated handle. Ammunition, danger areas and range templates are unaffected: the weapon remains a 7.62×51 mm NATO gun firing from disintegrating link.

Data Gaps

Several parameters remain unpublished. The Long Rail kit's unit price and any launch customer are not stated. The UK transparency notice does not break the £70 million down between new-build weapons, spares and support, nor indicate whether the contract contemplates optic-rail upgrades. Project Cairns has no published requirement, calibre or timeline. The Belgian EVOLYS purchase is an announced intent rather than a confirmed signature, and FMMG calibre and schedule are undecided in open sources. Fleet sizes for the L7A2 and M240 inventories are not given in the cited material. Confidence is assessed as moderate on the contractual and technical facts, which rest on government and manufacturer primary sources, and low on EVOLYS adoption detail, which rests on single-tier trade reporting.

Corrections & updates welcome. If you hold open-source data that refines or corrects any parameter in this article, please contact [email protected] citing the specific claim and your source. Verified corrections will be incorporated and credited in the revision history. AI-assisted technical assessment based on open-source material. Not a formal intelligence product.