檢視 IAR步槍的原始碼

{{Infobox Weapon
|name= Land Warfare Research Company Infantry Automatic Rifle
|image= 
|caption=
|origin={{flagcountry|United States}}
|type=[[light machine gun]]
<!-- Type selection -->
|is_ranged=yes
<!-- Production history -->
|designer= [[LWRC]]
|design_date= Unknown, Assumed to be 2006
|manufacturer=[[LWRC]]
|production_date= 2007-Present
|number=Unknown
|variants=[[LWRC SRT]]
<!-- Ranged weapon specifications --> 
|cartridge=[[5.56x45mm NATO]]
|action= [[Gas operated reloading|Gas operated]], [[Rotating bolt]]
|rate= 
|velocity= 
|range= 
|max_range= 
|feed= 30 round [[STANAG Magazine]]
|sights= 
}}

The '''LWRC (LWRCI) Infantry Automatic Rifle''' (IAR) is a variant of the [[LWRC SRT]], which is in turn, based on the [[AR-15|AR platform]] (specifically the [[M4 Carbine]]). It is designed to fulfill the role of the [[squad automatic weapon]]. Like the LWRC SRT, the LWRC IAR utilizes a [[Gas-operated reloading|gas-piston]] design in lieu of the AR's [[direct impingement]] design.<ref>[http://www.gec-intl.com/LWRIFLE.htm OFFER#<!-- Bot generated title -->]</ref> It was developed for the [[United States Marine Corps]] Infantry Automatic Rifle program, which seeks to replace the [[M249 SAW]] with a lighter, more reliable and durable [[5.56mm]] weapon.<ref>[http://hqinet001.hqmc.usmc.mil/p&r/concepts/2007/PDF/Chapter%203/Part%202/C&P2007Chap3%20Part2%20Ground%20Combat%20Element%20Pg159%20Infantry%20Automatic%20Rifl%20e.pdf X-15.indd<!-- Bot generated title -->]</ref> <br />

The weapon fires from a [[closed bolt]] in [[Semi-automatic rifle|semi-automatic]] mode, and from an [[open bolt]] during [[Automatic firearm|full automatic]] mode which is labeled as "OBA" for Open Bolt Automatic. While in OBA mode, the first round may be fired from a closed bolt (it will then lock back and subsequent shots will be from an open bolt until the operator manually closes the bolt again).

Firing from an open bolt increases cooling and eliminates the potential for accidental discharges due to rounds "cooking off" in an overheated chamber. It also allows for a faster rate of fire. However an open bolt design means that the first round fired will have reduced accuracy when compared to a closed bolt design. This is due to the fact that when the trigger is pulled, the bolt slams forward under spring tension, stripping a round from the feeding device, chambering it, then firing it. This sequence of events shakes the firearm and takes a (possibly crucial) split second longer than a closed bolt design to fire the first round (greater lock time). This also introduces extra potential points of failure in the ignition of the first round.

The IAR's ability to fire from both modes allows the gunner to deploy the weapon in OBA mode with a round chambered on a closed bolt. This allows the gunner to fire his first round as accurately, reliably, and quickly as a rifleman, while following that initial round with Squad Automatic Weapon (SAW) level of fire<ref>[http://www.gec-intl.com/LWRIFLE.htm OFFER#<!-- Bot generated title -->]</ref>

The plan is to have the USMC buy 4100 IARs to replace 2000 of the Corps SAWs. This will reduce the number of SAWs in the marine corps from 10,000 to 8000. The remaining 8000 M249s will be kept in service, as the M249 will not completely go away in the USMC. The Army has ruled out the option of replacing the SAW with the IAR, because it would result in a loss of fire going from 200 round belts to 30 round mags, and instead is looking into a new belt feed light machine gun such as the [[MK 46 LMG]]. [http://www.marinecorpstimes.com/news/2008/09/marine_iar_091308/]

The weapon was featured on the [[Discovery Channel]] show "[[Future Weapons]]" during its third season, under the first episode "Firepower".

==See also==
*[[LWRC SRT]]

==References==
{{Reflist}}

==External links==
[http://tampa.fbodaily.com/archive/2005/07-July/16-Jul-2005/FBO-00847676.htm]

[http://www.strategypage.com/dls/articles/20076825818.asp USMC Seeks new LMG]

[[http://www.lwrifles.com/forum/viewtopic.php?t=1138&highlight | Photos of IAR]]

[http://www.tactical-life.com/online/tactical-weapons/lwrcs-multi-mission-battle-rifle/]

{{AR-15 variants}}

[[Category:5.56 mm firearms]]
[[Category:Assault rifles]]
[[Category:Light machine guns]]