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by The Unitary Technocracy of Etoile Arcture. . 164 reads.

MG70B Universal Machine Gun

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

MG70B Universal Machine Gun

Type

Light machine gun,
squad automatic
weapon

Place of origin

Etoile Arcture

Service history

In service

2006 - present

Used by

See Users

Production history

Designer

Sequoia Weaponworks

Designed

2002-2004

Manufacturer

Sequoia Weaponworks

Unit cost

US$4,000

Number built

A great many I dare say

Variants

  • MG70B Universal
    Machine Gun

  • MG71KB Universal
    Machine Gun

  • Specifications

    Weight

    8.2-8.5 kg

    Length

    1040 mm or 1220 mm

    Barrel length

    419 mm or 571.5 mm


    Cartridge

    6.5×39mm Grendel

    Action

    gas operated,
    piston driven,
    short stroke

    Rate of fire

    650-850 rounds/min

    Muzzle velocity

    820 m/s

    Effective firing range

    • Bipod: 700 m

    • Tripod: 1,100 m

    Maximum firing range

    3,600 m

    Feed system

    200-round M27-style
    disintegrating metallic
    split-linked belt, nylon
    pouch-like drum magazine

    Sights

    rear peep and hooded
    front post, day optics,
    etc

    The MG70B Universal Machine Gun (UMG) is a gas piston-operated, air-cooled, fully automatic, belt fed lightweight machine gun firing from the open bolt position with positive locking. The MG70B is part of the same family as the G500 Modular Weapon System (G500 MWS) being chambered in a common cartridge, the 6.5×39mm Grendel, which offers advantages in terminal ballistics and knockdown power and allows for logistics harmonisation. As a "universal" machine gun the MG70B is light enough to be employed in the role of a squad automatic weapon (SAW) providing the basis of fire for the infantry section/fire team, and can fulfil the belt-fed sustained fire role at platoon/company level when mounted on a stabilised tripod. Construction is also similar to the G500 MWS, with a polyamide receiver body reinforced by a stamped and welded sheet-metal frame, and a MIL-STD-1913 Picatinny rail interface system for mounting accessories such as day optics and thermal sights to enhance accuracy. The MG70B consists of a two model family including the base MG70B model with 22½ inch barrel (below) and the MG71KB model that features a shortened 16½ inch barrel (top) that allows manoeuvring within confined spaces.

    Description


    The rectangular box-shaped receiver is constructed from highly durable GF/PA-6 glass fibre/polyamide-6 thermoplastic moulded over an internal sheet-metal skeletonised frame. This internal frame is formed from 1.75 mm sheets of AISA 1018 low carbon steel that is die cut, stamped on a precision mandrel and welded to form a reinforcement insert that is secured with high torque steel cross-bolts. Furniture including the buttstock, pistol grip/trigger guard and ventilated fore-end heat shield are of all-polymer construction, with MIL-STD-1913 Picatinny rails moulded onto the lower receiver, upper receiver/feed cover and heat shield. Optical sights and clip-on thermal or night vision devices can be mounted in-line on the upper rails. The basic iron sights consists of a low profile rear adjustable tangent leaf and peep sight granulated for ranges from 100 to 1,000 metres using an elevation adjustment drum, and a hooded post fore sight adjustable for windage and elevation, with Tritium luminous dots for low light/night shooting.
    The gas system, manual regulator, bolt group and feed tray are made from AISI 8620 chrome-plated alloy steel, and the free-floating, non-fluted, no-tools quick change, cold rotary hammer-forged barrel from AISA 4140 chrome-moly-vanadium (CMV) high tensile steel. The barrel has a fixed head space and is replaceable in only three seconds. A Stellite (high carbon cobalt alloy) liner is press-fitted into the chamber and rifling to provide wear and erosion resistance to ensure the longest accuracy and service life of the barrel. The barrel is fitted with a three port open-end flash hider that lacks a downward facing port that can blowback dust and dirt to reveal a shooter's location to the enemy. Internally the bolt carrier rides on steel guide rails inside the boxy receiver, along with a guide rod and oil-proof polyurethene multi-strand recoil and return springs. The feed mechanism is located on top of the receiver and is driven by a single sprocket. All exposed steel parts have a manganese phosphate corrosion resistant and rust-proof finish, and are coated in molybdenum-disulphide dry-film lubricant for near maintenance-free operation.
    The weapon has a side-folding skeletonised buttstock that provides an off hand grip hook for added stability and can be fired without affecting accuracy with the stock folded to reduce length in confined areas. A silicone rubber recoil pad fitted against the butt plate and in-line recoil path in combination with the free floating barrel significantly reduces felt recoil thereby increasing reliability and accuracy. A collapsible aluminium bipod is attached to the gas block, and the MG70B can be ground mounted for the sustained fire role on a lightweight tripod with traverse and elevation control mechanism, or can be pintle mounted on a vehicle.
    A weapon kit will typically consist of a machine gun with blank firing attachment (BFA), a spare barrel, integral reciever and MIL-STD-1913 rail accessory system, diopter iron sights, spring-locked folding buttstock, four 200 round polymer box magazines and four 200 round nylon soft pouch magazines, a folding bipod, two QD sling swivels, and a two-point tactical sling. The standard maintenance kit includes bore, chamber and receiver cleaning brushes, a multi-section cleaning rod, a cartridge extractor, and a combination tool. A laminated instruction manual and range cards are also supplied. The weapon is advised to be issued with a M122 or M192 style tripod and aftermarket optics if deployed in the sustained fire role.

    Operating principles

    The operating system is a short stroke gas piston with a gas tube located underneath the barrel, using gas tapped from the forward part of the barrel to move the bolt carrier to cycle the weapon. The bolt carrier rotates the bolt via a cam to lock and unlock multiple radial lugs that engage a barrel extension to chamber a round. This sequence operates in the strict reverse upon firing to unlock and extract an empty case from the chamber. The radial locking lugs distribute the firing load evenly around the bolt head and barrel extension to reduce stress on these components for increased longevity. The weapon is fired from the open-bolt position using a free-floating firing pin to prevent ammunition cookoff and excessive barrel heating. A four-port gas regulator permits the cyclic rate to be varied between 650 to 850 rpm to preserve barrel life from heat damage, with additional positions to clean the piston and provide extra power in adverse environmental and operational conditions.
    Ammunition is fed from the left using M27-style disintegrating metallic split-linked belts. The belts are loaded from either a 200 round capacity moulded polymer box magazine or a zippered nylon pouch ammunition drum, both being clipped to the side of the receiver with an adaptor. The basic recommended ammunition loadout for a gunner and assistant gunner is 600-1,000 rounds. The belt feed is a push-through type operated by a roller on the top of the bolt carrier and guided by dual feed-pawls. The feed cover and the ejection port are both protected by spring-loaded dust covers. Spent links and shells eject to the right at a 10° angle away from the firer to help conceal battle positions and avoid striking tripod or pintle mounts.
    The operator controls are of near-identical design to those used on the G500 MWS allowing for easy training conversion/familiarisation by personnel. These consist of a trigger with a crisp single-stage pull and ambidextrous safety/selector switch with a tactile click between fire modes. The trigger group allows to execute single shot (semi-auto fire) to engage point targets with accurate shots, and full-auto fire for sustained suppressive fire against area targets. The cocking handle is mounted on the right side of the receiver and is non-reciprocating. Safety mechanisms include an inertial safety to prevent accidental or negligent discharge of the weapon when jolted or dropped and an anti-runaway device (ARD) to prevent the weapon firing uncontrollably after the trigger has been released. When set to 'Safe' a sear/disconnector blocks the trigger and locks the bolt in the cocked position allowing the MG70B to be safely carried at Condition One (with bolt retracted, safety on, belt in feed way) for instant employment.

    Product Improvement Program

    Both new-build and existing MG70B models have been upgraded with a Product Improvement Program (PIP) kit incorporating a number of user-specified changes and improvements based on operational experience. These include:

    • Swapping the original hard polymer high-capacity magazine with a new soft nylon pouch-like drum magazine. This was made in response to user complaints about linked belts rattling inside the rigid housing, and the high profile of the magazine that restricted gunners movements when moving and firing while prone. The new soft pouch drum is wider but shorter to maintain capacity while addressing these complaints.

    • New high-profile heat shield with rail accessory system (RAS). Users had complained that despite the full size rail on the feed cover the rail length was still insufficient to mount both a day optic and clip-on thermal sight to provide day/night magnified vision. This forced gunners to choose between using magnified optics during the day and un-magnified night vision devices at night. The new RAS is mounted on a taller heat shield, which also provides better thermal performance allowing longer sustained firing, and will allow a clip-on thermal sight to be mounted ahead of a magnified day optic during night operations.

    • Under-the-receiver Picatinny rail. This short section of rail allows mounting of a vertical grip ahead of the handguard located near or at the weapon's centre-of-gravity, allowing the gunner to manoeuvre their weapon more efficiently.

    Variants


    MG70B Universal Machine Gun

      MG71KB Universal Machine Gun

        Users


        Etoile Arcture

        • Etoile Arcture Ground Forces: provides the basis of fire at the fireteam, squad, platoon and company level.

        Arcturia

        • Armée de Terre

        • Corps des Marine

        Madurastan

        • Madurastan Army

        Zinaire

        • Zinarian Army

        Sarrowquand

        • Dominion Standard Regular Army

        Parilisa

        • Parilisan Revolutionary Army

        Central prestonia

        • Royal Army

        Burtilana

        • Burtilanan Army

        Cazatania

        • Cazatanian Army

        Minnysota

        • Minnysotan Army

        Salcania

        • Salcanian Army

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        Specifications


        • Cartridge: 6.5×39mm Grendel

        • Action: gas operated, piston driven, short stroke

        • Locking: rotary bolt w/ 4 radial lugs

        • Weight: 8.2-8.5 kg fully loaded

        • Overall length: 1040 mm or 1220 mm

        • Barrel length: 419 mm or 571.5 mm

        • Rifling: three lands and grooves, right hand twist, 1 turn in 178 mm

        • Muzzle device: three port open-end flash hider

        • Feed type: 200-round M27-style disintegrating metallic split-linked belt, nylon pouch-like drum magazine

        • Sights: rear leaf and hooded front post, day optics, etc

        • Muzzle velocity: 820 m/s

        • Effective range: 700 m vs point targets, 1,100 m vs area targets,

        • Maximum range: 3,600 m

        • Fire control: drop-in replaceable trigger group, ambidextrous selector levers

        • Rate of fire: 50-200 rpm practical, 650-850 rpm cyclic

        • Trigger pull: single-stage Match, non-adjustable 13.34 N pull

        • Unit replacement cost: US$4,000

        RawReport