{{Short description|155 mm base bleed artillery round}} {{Update|date=December 2022}} [[File:XM1128-155mm.jpg|thumb|right|upright=1.35|Cutaway view of M1128 round]] The '''M1128''' "Insensitive Munition High Explosive Base Burn Projectile" is a {{nowrap|[[155 mm]]}} boosted artillery round designed to achieve a maximum range of {{convert|30|-|40|km|mi}}. It is used for fragmentation and blast effect against personnel and/or materiel. The development of this round follows testing of (and is based on aspects of) boosted [[M795]]-series test projectiles. The M1128 is not yet in production, but the first successful test firings have already taken place.<ref name=nguyen11>{{cite web |url=http://www.dtic.mil/ndia/2011gunmissile/Tuesday11528_Nguyen.pdf |title=M1128 Insensitive Munition High Explosive Base Burn Projectile |first=Ductri |last=Nguyen |publisher=Department of the Army |agency=Office of the Project Manager for Combat Ammunition Systems |date=30 August 2011|archive-url=https://web.archive.org/web/20150513030125/http://www.dtic.mil/ndia/2011gunmissile/Tuesday11528_Nguyen.pdf |archive-date=2015-05-13 }} {{PD-icon}}</ref>
The M1128 is expected to be compatible with a nose-mounted guidance system—specifically, the [[XM1156 Precision Guidance Kit]], which fits the standard fuse threading common to several types of rounds.<ref name=lyle>{{cite web |url=http://www.dtic.mil/ndia/2012fuze/13680Johnson.pdf |title=Precision Guidance Kit |first=Lyle H. |last=Johnson |publisher=National Defense Industrial Association |archive-url=https://web.archive.org/web/20120927212628/http://www.dtic.mil/ndia/2012fuze/13680Johnson.pdf |archive-date=2012-09-27 |agency=Alliant Techsystems |author-link1=Alliant Techsystems}}</ref>
==Development== The design program for the M1128 was established in FY2011 with the stated purpose of addressing USMC requirements for artillery ammunition capable of {{convert|30|-|40|km|mi}} range. It is also designed for improved accuracy. It carries a larger payload than the aging [[M549]] Extended Range Projectile or ERP, which is the previous boosted round the M1128 is designed to replace.<ref name=nguyen11/> The M1128's range of {{convert|30|km|mi}} far exceeds conventional (non-boosted) artillery rounds such as the [[M107 projectile]] which has a {{convert|17|km|mi}} range.{{Cn|date=January 2021}}
The Army is currently in the process of adopting the [[USMC]] requirement for the M1128. Once approved, the plan for the M1128 is to enter the Engineering & Manufacturing Development Phase in the acquisition process as a fully funded program. Tooling and processes have been developed and the initial production batch has been delivered to the proving grounds for testing by [[USMC]] resources.<ref name=ndia>{{cite web |url=http://proceedings.ndia.org/1590/11528.pdf |title=Proceedings Abstract #11528 |publisher=National Defense Industrial Association}}</ref>
==Details== The M1128 follows (and is based on) production and test articles from the boosted M795-series rounds—specifically the M795E1 and M795E2.<ref name=nguyen11/>
The M1128 consists of a high fragmentation steel body with a streamlined ogive and a drag-reducing base burner. The projectile body is filled with insensitive explosive ([[IMX-101]]) and a supplementary charge. On gun launch propellant gases enter the base burner cavity and ignite dual tracer cups in the ignition assembly. The tracer cups then light a composite propellant to sustain the burning at muzzle exit. The roughly three pound base propellant charge gases, ignited during firing, fill the low pressure void at the base of the projectile, this reduces the base drag and results in extended range.<ref name=nguyen11/>
The base-bleed solution yields a more consistent ballistic trajectory, which reduces the [[Range Probable Error]] or RPE. (See also [[Circular Error Probable]].) The M1128 uses the "base burn" or "[[base bleed]]" assembly.<ref name=nguyen11/>
==Used with== * [[M109 howitzer|M109]] * [[M114 155 mm howitzer|M114]] * [[M198 howitzer|M198]] * [[M777 howitzer|M777]]
==See also== *[[M549]] *[[M795]] *[[M107 projectile|M107]] *[[List of artillery]]
==References== {{reflist}}
[[Category:155 mm artillery shells]] [[Category:Artillery shells]] [[Category:155 mm artillery]]