by Max Barry

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by The Unitary Technocracy of Etoile Arcture. . 104 reads.

GL18E2 Basilisk multi-shot grenade launcher

This page is a work in progress by its author and should not be considered final.

GL18E2 "Basilisk"


Multi-shot grenade launcher

Place of

Etoile Arcture

Service history

In service

2015 - present

Used by

See Users

Production history


Sequoia Weaponworks




Sequoia Dynamics Armaments And Technical Products
Korrodos Military Dynamics (under license)

Unit cost


Number built



See Variants



5.8 kg fully loaded with sight


736 mm stock folded, 800 mm stock extended

Barrel length

254 mm (10 in)


  • 40×46mm low-velocity (LV)

  • 40×51mm medium-velocity (MV)

  • Action

    double action

    Rate of fire

    120 rpm cyclic,
    20 rpm practical

    Muzzle velocity

  • LV: 79 m/s

  • MV: 105 m/s

  • Effective firing

  • LV: 125 m point targets, 375 m area targets

  • MV: 250 m point targets, 700 m area targets

  • Maximum firing range

  • LV: 400 m

  • MV: 800 m

  • Feed system

    6 round rotating drum


    Armson single point OEG collimator sight, M2A1 reflex sight, Mepro GLS reflex sight, etc in quadrant

    The GL18E2 Tactical Support Weapon (TSW), popularly known as the "Basilisk", is a lightweight, shoulder-fired, air-cooled, gas operated, semi-automatic, revolving action, six-round 40 mm (1.57-inch) calibre multi-shot grenade launcher that offers a high volume of fire to support infantry operations. It can load and fire the full continuum of 40×46 mm low-velocity (LV) and 40×51 mm medium-velocity (MV) grenades with a 140 mm chamber length that accommodates all standard length lethal and extended length less-lethal, as well as enhanced hyper lethal and speciality grenade rounds.
    The GL18E2 operates by revolver principle using a ratchet-driven, gas operated six-chamber cylinder to achieve a high rate of accurate fire which can be rapidly brought to bear on a target. For offensive or defensive operations such as ambush/counter-ambush and close combat a full six round salvo can be fired in only 3 seconds to effectively cover a minimum destruction area of 20 by 60 metres at ranges up to 400 metres. For crowd/riot control and security operations the launcher can accurately engage or suppress point targets out to 125 metres with pin point direct fire accuracy with lethal or less-lethal ammunition. The GL18E2 is highly controllable and accurate with soft recoil and shallow ballistic trajectories when using medium-velocity ammunition.



    The GL18E2 consists of six components: a barrel and front frame group, a cylinder (drum magazine) that revolves around a central axis, a rear frame and trigger mechanism, a reflex or occluded eye gunsight mounted in quadrant, and a adjustable shoulder stock. The frame is machined from a solid billet of Ergal 7075-T6 aluminium alloy that possesses steel-like mechanical strength and durability qualities, and the cylinder die-cast from corrosion resistant Delphi K-Alloy/A304 in a hot chamber machine. The free-floating barrel is buttoned rifled from AISA 410 stainless steel with a progressive gain-twist that extends barrel life by reducing wear and imparts greater rotational stability on grenades to enhance their accuracy.
    The barrel is surrounded by a lightweight ventilated heat shield cut with integral Vltor KeyMod accessory rails along the sides. A MIL-STD-1913 Picatinny full-length sight rail is fitted to the receiver top, and a short section of bottom rail mounts a vertical grip. The furniture includes a hard rubber-like Kraton G pistol grip and a polymer collapsible shoulder stock that contains a recoil buffer with self-regulating hydraulic shock absorber to attenuate the firing impulse. The stock is attached to the rear frame by a three-position swivel mount that can be set at various superelevation angles to match high to low angle ballistic trajectories, and is four-position collapsible for adjustment of eye relief.

    Operating principles

    The GL18E2 is striker fired by a spring-loaded firing pin and has a gas operated locking system that functions in similar fashion to a revolver pistol. The semi-automatic mechanism is cycled by gas diverted from the barrel by a tappet to drive an operating piston that in turn advances the cylinder via a rachet mechanism indexed by a chamber alignment pin. Fire control is by ambidextrous safety/selector lever and a constant pressure double-action (DA) trigger. Each pull of the trigger rotates the cylinder one-sixth of a revolution, bringing a fresh chamber in battery with the barrel, automatically cocking the striker and releasing the firing pin to hit a percussion primer to fire the grenade. The trigger is two-stage with a long and heavy pull and short surprise break for flinch-free accurate placement of shots. In event of a dud round or misfire a release button on the frame can be pressed to unlock the cylinder allowing it to rotate freely to clear the affected chamber.
    In addition to a manual safety the GL18E2 has several automatic safety features including a no-skip device to prevent the cylinder advancing unless the previous round has been fired or manually cleared, and a transfer bar drop safety that keeps the firing pin out-of-line with the firing pin hole until the trigger is pulled all the way back. Ambidextrous release levers on the rear and front frame control a locking mechanism that allows the entire drum to swing open sideways out of the frame to provide access to the six ammunition chambers to reload the weapon with 40 mm cartridges. The gas operating system is superior in performance to other foreign competitor designs that rely on a manually wound clockwork spring mechanism to cycle the weapon, allowing the GL18E2 to be brought into action much faster upon loading/reloading and to fire at a faster firing rate.


    The sight rail of the GL18E2 can accept a wide variety of aftermarket reflex (red dot), holographic and quadrant sights when firing at ranges <400 m, such as the Milkor M2A1, Rippel Effects GR40 and Mepro GLS reflex sights. It is most optimally configured when equipped with a both-eyes-open single point collimating sight like the Armson O.E.G. (Occluded Eye Gunsight). The O.E.G. compensates for ballistic drift of the 40 mm grenade, and includes a reticule design that allows quick aiming-point adjustment and range estimation, a range quadrant graduated in 25 metre increments, and tritium illuminated aiming posts for low light operation. At ranges up to ~800 m a aftermarket target acquisition and fire control system (FCS) is recommended, such as the Hensoldt Fire Control Sight, Rheinmetall Defence Vingmate Multi-Ray 800 and ITL Viper, that combine a daylight and nighttime (thermal) CCD channel, laser rangefinder, inclinometer, ballistic computer, ammunition programmer, and induction loops installed in the grenade launcher barrel. The FCS can program electronic timed air-burst munitions using range data gathered by the sight to engage targets in defilade such as behind reverse slopes and walls, and reaching building occupants through openings.


    The GL18E2 is a standalone grenade launcher and only one variant is produced, but can differ in the various types of optical or electronic sights used.


    Etoile Arcture

    • Etoile Arcture Ground Forces

    • Etoile Arcture Special Forces


    • Armée de Terre

    • Corps des Marine

    • Forces Spéciales


    • Royal Imbrinium Army

    • Royal Imbrinium Marine Corps


    • Imperial Army


    • Astograthian Army

    Monavian Empire

    • Monavian Royal Marine Corps

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    • Cartridge: 40×46mm low-velocity and 40×51mm medium-velocity grenades, including HE, HEDP, thermobaric, canister, baton, speciality, etc

    • Operation: double action, gas operated, semi-automatic

    • Overall length: 736 mm stock folded, 800 mm stock extended

    • Barrel length: 254 mm9

    • Rifling: right hand twist, progressing from 0 to 1 turn in 1.2 m at muzzle

    • Feed device: 6 rounds, revolver action, drum magazine

    • Sights: aftermarket reflex sights, occluded eye gunsights, electronic fire control sights, etc

    • Muzzle velocity: 79 m/s low-velocity, 105 m/s medium-velocity

    • Effective range: 125 m low-velocity, 250 m medium-velocity

    • Maximum range: 400 m low-velocity, 800 m medium-velocity

    • Fire control: ambidextrous selector levers

    • Trigger pull: two stage, adjustable 40-65 N pull

    • Unit replacement cost: US$1,500