Editing FN F2000 (section)

==Design details==
{{More citations needed section|date=November 2021}}
The F2000 is a modular weapon system; its principal component is a compact [[5.56×45mm NATO]]-caliber [[assault rifle]] in a [[bullpup]] configuration. The F2000 is a [[selective fire]] weapon operating from a [[closed bolt]].

The rifle consists of two main assemblies: the barreled [[receiver (firearms)|receiver]] group and the frame, coupled together by means of an axis pin located above the trigger guard. The barrel group has an integral MIL-STD-1913 [[Picatinny rail]] used to mount optical sights. The frame or lower receiver contains the trigger group, the bolt and bolt carrier assembly, return mechanism and magazine well. A removable handguard is installed in front of the trigger which completes and encloses the trigger guard.

===Features===
The F2000 is a gas-operated, fully automatic and ambidextrous bullpup rifle. Both the safety system and trigger mechanism were adopted from the [[FN P90|P90]] [[personal defense weapon]]; the selector toggle is a rotating disc located below the trigger. The fire selector doubles as the weapon's manual safety and secures the firearm against accidental discharge (the selector/safety disc has 3 settings: "S" safe, "1" [[Semi-automatic firearm|semi-automatic]] mode, "A" fully automatic fire). The "safe" setting disables the trigger. The hammers, group pins, and springs are steel while all other components are nylon injection molding. The shell of the rifle is made of composite materials.

The F2000 is fed from standard [[NATO]] box [[magazine (firearms)|magazines]] ([[STANAG magazine|STANAG 4179]]) with a 30-round cartridge capacity using [[5.56×45mm NATO|5.56×45mm]] ammunition. The magazine catch/release button is installed symmetrically in the pistol grip, in front of the magazine; the magazine catch is operated by an oversized actuator useful when wearing [[NBC suit|NBC]] gloves. The F2000 is not configured from the factory to have a drop-free magazine system due to the friction from the removable dust gaskets. The magazine needs to be pulled out manually.

The rifle does not have a hold-open device; the bolt does not stay back after the last round is fired. The charging handle is placed on the left side of the receiver, just above the hand guard, and can be operated by left-handed shooters. There are no access points for the possible ingress of dirt or debris; the charging handle slot is sealed.

The weapon's primary sight is a telescopic sight with a fixed 1.6× magnification (the reticle also enables use in low-light conditions) contained in a plastic housing above the receiver (mounted on the MIL-STD-1913 rail), the secondary sight is a non-adjustable fixed notch and front blade, molded into the optical sight housing cover. The sight cover and sight module can be quickly removed to reveal the Picatinny rail.

The rifle's chromed hammer-forged [[steel]] barrel is stated to retain accuracy after 20,000 normal (non-sustained) rounds. The barrel also features a [[flash suppressor]] with an angled cut at the tip which directs the muzzle blast upward, compensating for muzzle rise. The F2000 has an optional [[bayonet]] lug mounted near the muzzle, and an adjustable gas regulator with two settings: "normal" for standard ammunition meeting NATO specifications, and "adverse", used to send an increased volume of gas into the system to ensure proper functioning when fouled or when using low-pressure ammunition.

===Operating mechanism===
[[File:FN F2000 partially disassembled.jpg|thumb|left|Partial disassembly (cartridge on bolt face)]]

This [[selective fire]] weapon is a [[Gas-operated reloading|gas-operated]] design utilizing a short-stroke piston system driven by propellant gases diverted into the gas cylinder through a port in the barrel; it fires from a closed bolt position. The weapon is locked with a rotating bolt which features 6 radial locking lugs, a spring-powered [[extractor (firearms)|extractor]] and ejector. The [[chamber (firearms)|chamber]], bolt, and ejector mechanism can be accessed by flipping up a hinged inspection cover in the receiver, behind the optical sight housing.
[[File:PISTONM16.gif|thumb|left|short-stroke gas piston]]

The F2000 uses a unique ejection system, ejecting spent cartridge casings forward and to the right side of the weapon, through a tube running above the barrel. This method of ejection provides for fully ambidextrous operation; the rifle can be used without any modification by both right and left-handed shooters. This ejection pattern was achieved by using a swiveling polymer tray, which intercepts the empty casing from the bolt face immediately after disengaging from the extractor. As the empty casing is extracted it is held while the rocker assembly tilts to lift it above and clear of the feed path as the next round is stripped from the magazine by the bolt head. The casing is fed into the tray located in a cavity in the receiver wall, which then pivots the cartridge case and directs it into a chute (above the barrel); the case is discarded from the tilting tray by being impacted by a pin on the moving bolt carrier upon its forward return. Only when the ejection tube contains more than five cases is the first of them ejected forward through a port just behind and to the right of the muzzle. Any cases remaining after firing has ceased, can be cleared by tilting the rifle muzzle down.

This system is patent protected (patent number 5675924 dated 14 October 1997 by René Predazzer<ref>{{cite web |url=https://patents.google.com/patent/US5675924 |title=Ejection device for firearm |author=Predazzer, Rene |work=Google Patent Search }}</ref> and patent 6389725 from February 25, 2000, author Charles Denuit).<ref>{{cite web |url=https://patents.google.com/patent/US6389725 |title=Fire arm with forward ejection or ejection brought to the fore-part of the firearm |author=Denuit, Charles |work=Google Patent Search }}</ref> The ambidexterity provided by forward ejection is its most obvious benefit, and removes many of the tactical and user difficulties (such as lack of ambidexterity, and gas and debris released in close proximity to the shooter's face, as in the [[SA80]] or [[OC-14]]) that bullpup designs usually create.

===Grenade launcher===
[[File:FN GL1.png|thumb|GL1 grenade launcher, not mounted]]
[[File:Pripadnik Slovenske vojske.jpg|thumb|GL1 mounted on F2000]]

One of the modules developed for the F2000 system is a proprietary lightweight 40&nbsp;mm underslung GL1 grenade launcher (empty weight 1&nbsp;kg) that uses standard low-velocity [[40&nbsp;mm grenade|40×46mm]] grenades.<ref>[http://www.fnherstal.com/index.php?id=271&backPID=265&productID=89&pid_product=297&pidList=265&categorySelector=7&detail= GL1 40&nbsp;mm LV] {{webarchive|url=https://web.archive.org/web/20090322012754/http://www.fnherstal.com/index.php?id=271&backPID=265&productID=89&pid_product=297&pidList=265&categorySelector=7&detail= |date=2009-03-22 }}, FNHerstal.com</ref> The launcher is a single-shot breech-loaded reverse [[pump-action]] weapon with a barrel that slides forward for loading and unloading (like the [[M203 grenade launcher]]), locked by axial rotation of the barrel.<ref>{{cite web|url=http://www.fnherstal.com/typo3temp/pics/a417e702b9.jpg|title=Pictured: FN F2000 Standard with Grenade Launcher|website=fnherstal.com|access-date=7 May 2018|url-status=dead|archive-url=https://web.archive.org/web/20160304065827/http://www.fnherstal.com/typo3temp/pics/a417e702b9.jpg|archive-date=4 March 2016|df=dmy-all}}</ref>

The grenade launcher's trigger is installed directly under the F2000's trigger so that it can be manipulated without removing the shooting hand from the rifle's pistol grip.<ref>{{cite web|url=http://www.fnherstal.com/uploads/pics/f2000_std_trigger1.jpg|title=F2000 pictured with standard trigger and GL1 grenade launcher with flip up sights|website=fnherstal.com|access-date=7 May 2018|url-status=dead|archive-url=https://web.archive.org/web/20150924014256/http://www.fnherstal.com/uploads/pics/f2000_std_trigger1.jpg|archive-date=24 September 2015|df=dmy-all}}</ref> The double-action trigger lets the operator "try again" if the grenade's percussion type primer doesn't ignite. The breech release button is found on the left side of the launcher body, like on the M203. The grenade launcher comes with a basic flip-up ladder sight, but it was intended to be used with a specially designed optoelectronic fire control system designated FCS, developed in cooperation with the Finnish company Noptel.

The aiming module is installed in place of the standard optical sight and becomes the weapon's primary sight when mounted, but its main purpose is to accurately determine and indicate the range of a grenade target. The module is powered by a 9 V battery pack, installed in the stock, behind the magazine well. The power pack is also intended to power any other tactical accessories or systems that could be introduced. The FCS integrates a low-power laser rangefinder (precise to within ± 1 m), a day-time aiming channel with an electronically projected reticle, a measured range display reading and a diode elevation adjustment indicator.

The fire control system calculates a firing solution manifested by the barrel's angle of elevation using target range information from the laser rangefinder (the rangefinder is activated by pushing a button on the pistol grip, below the trigger), corrected manually by the shooter through a push-button interface (add/subtract buttons) on the FCS top cover to take account for head or tail winds that could affect the desired range. The F2000 FCS also contains software with the ballistic properties of up to six types of 40&nbsp;mm grenades and can be reprogrammed to take advantage of future munition improvements. Batteries for the FCS are located in the bottom of the buttstock.

After obtaining a range measurement, the distance to the target is displayed on a [[liquid crystal display|liquid crystal]] screen and the elevation diode flashes red. Once a correct elevation has been achieved by tilting the rifle, the diode changes color to green indicating the weapon is ready to fire{{citation needed|date=February 2013}}