Description
This XM21 Armament System Door Filler, identified by FSN 1005-832-5811 and Part Number 11697556, is a specialized military-surplus component associated with U.S. helicopter armament support hardware. For collectors of Vietnam-era aviation equipment, helicopter armament subsystem components, U.S. military surplus parts, and part-numbered ordnance hardware, this is a focused reference item with strong catalog and display value.
The XM21 / M21 Armament Subsystem is historically tied to the UH-1 Huey gunship era. U.S. Army historical material identifies the M21 Armament Subsystem as a significant UH-1 weapons subsystem that combined M134 7.62-mm machine gun equipment with M158 or M158A1 2.75-inch rocket launchers during the Vietnam War period. The same Army article also identifies a full XM21 subsystem shown aboard a UH-1B Huey, placing this equipment family directly within the history of U.S. helicopter armament development.
The XM21 Door Filler
The Door Filler belongs to the broader family of helicopter armament subsystem support components, mounting hardware, aviation ordnance accessories, and U.S. military replacement parts. Unlike a complete armament subsystem, firearm, launcher, or ammunition item, this is an individual support component identified by its stock number and part number.
Available Army repair-parts documentation confirms the exact stock-number and part-number combination as a Filler Assembly, Door under a helicopter armament subsystem Mount Assembly. The listing identifies FSN 1005-832-5811, Filler Assembly, Door, P/N 11697556, with quantity EA 1 in the mount assembly listing.
For collectors, that gives this item added appeal. It represents the smaller support hardware behind larger aviation armament systems, helping preserve the technical, maintenance, and supply-chain side of U.S. military helicopter equipment rather than only the more recognizable weapons, aircraft, or manuals.
Known Catalog Details
This component is especially useful for buyers who collect, catalog, restore, or display military surplus parts by official-style identification numbers.
Known information includes:
- Item: XM21 Armament System Door Filler
- Catalog Nomenclature: Filler Assembly, Door
- Federal Stock Number: FSN 1005-832-5811
- Part Number: 11697556
- Reference / Manufacturer Code: 02731
- Manufacturer Code Reference: Hughes Tool Company – Aircraft Division, Culver City, California
- Item Type: Military-surplus helicopter armament subsystem component
The Army parts-list source identifies manufacturer code 02731 as Hughes Tool Company – Aircraft Division, adding useful traceability for collectors who value original part-numbered aviation ordnance components.
What This Component Supports
As an XM21 Armament System Door Filler, this item is best understood as a support component for a larger helicopter armament subsystem. It is not a complete armament system, not a firearm, not a launcher, not ammunition, and not an explosive item.
In practical collecting and display terms, a component like this is especially relevant for:
- XM21 / M21 armament subsystem displays
- Vietnam-era UH-1 Huey equipment collections
- helicopter armament hardware reference collections
- U.S. military surplus aviation parts collections
- museum exhibits on helicopter gunship systems
- restoration or completion of armament-subsystem display assemblies
Because available public parts-list data confirms the FSN 1005-832-5811 / P/N 11697556 identity as a Door Filler Assembly, buyers working on a specific restoration or installation should verify fitment against their own aircraft, mount, or technical manual documentation before purchase.
Historical and Technical Interest
The XM21 / M21 equipment family is closely tied to the rapid development of helicopter armament during the Vietnam War. The UH-1 Huey became one of the most recognizable aircraft of that conflict, and the Army developed numerous armament subsystems, mounts, sights, and support components to adapt the platform for gunship and fire-support roles.
Small components like this Door Filler help tell the support story behind those larger systems. While complete aircraft and armament packages receive most of the attention, military logistics depended on individual parts, assemblies, panels, fillers, mounts, brackets, and hardware that allowed systems to be maintained, cataloged, repaired, and supported through official supply channels.
For collectors and historians, this component is especially relevant to subjects such as:
- XM21 Armament System components
- M21 Armament Subsystem history
- UH-1 Huey gunship equipment
- Vietnam War helicopter armament
- M134 Minigun support hardware
- helicopter ordnance mounting components
- U.S. Army aviation ordnance support systems
Because this is a specific part-numbered component rather than a general surplus item, it adds focused technical depth to collections centered on helicopter armament, Vietnam-era aviation, and U.S. military supply-system hardware.
About This Door Filler
This listing is for one XM21 Armament System Door Filler, identified as FSN 1005-832-5811 and P/N 11697556.
It is especially well suited for:
- XM21 and M21 armament system collectors
- UH-1 Huey aviation-equipment displays
- Vietnam War helicopter gunship collections
- U.S. military surplus component collections
- ordnance support equipment displays
- museum and archival reference use
- buyers seeking P/N 11697556 or FSN 1005-832-5811
This listing is for the door filler component only unless otherwise stated. No complete armament system, aircraft, weapon, launcher, ammunition, mount assembly, tools, manuals, or additional accessories are included unless specifically shown or noted.
Why This Door Filler Matters
Many military collectibles focus on complete weapons, aircraft, uniforms, helmets, manuals, or large display pieces. This item represents a different but equally important category: the individual support components that kept aviation armament systems documented, maintained, and supplied.
For collectors, it is a compact and highly specific helicopter armament component with clear FSN and part-number identification. For researchers, it provides a useful reference point for how small aviation ordnance components were cataloged. For museums and displays, it helps show the behind-the-scenes hardware that supported larger UH-1 Huey armament systems during the Vietnam War and Cold War period.
Because this item is tied to the XM21 Armament System and carries the traceable identification FSN 1005-832-5811 and P/N 11697556, it is a strong fit for anyone building a focused collection of U.S. helicopter armament components, Vietnam-era aviation equipment, or government-surplus ordnance support hardware.
Ideal For
This door filler is a strong fit for:
- XM21 Armament System component collections
- M21 Huey gunship equipment displays
- Vietnam War helicopter aviation collections
- U.S. Army aviation ordnance reference collections
- military surplus hardware collectors
- museum and archival display setups
- buyers seeking P/N 11697556 / FSN 1005-832-5811
Approx length 9", Approx width 8", Approx height 1", Approx weight 1lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item's general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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