Description
U.S. Army M102 105mm Howitzer Drum, Roller Assembly, P/N 8427021, NSN 1015-00-738-4279
This U.S. Army Drum, Roller Assembly, identified by part number 8427021 and NSN 1015-00-738-4279, is part of the rear roller-tire and traversing system used on the M102 105mm Light Towed Howitzer.
The metal drum forms the core of the M102's rear roller assembly. With the separate roller tire installed around it, the assembly rides beneath the rear of the box trail and allows the emplaced howitzer to rotate around its firing platform.
This is an inert gun-carriage component, not ammunition.
Historical Significance
The M102 was developed as a lighter replacement for the older M101A1 105mm howitzer. Its aluminum-alloy carriage and low-profile design made it much better suited for airborne and airmobile artillery units.
The M102 entered U.S. Army service during the 1960s and began reaching artillery units in Vietnam in 1966. Its lighter weight allowed it to be moved by helicopter and smaller vehicles, an important advantage for artillery units operating from remote firebases.
One of the M102's most important improvements was its full 6,400-mil, or 360-degree, traverse capability. Instead of digging up and repositioning the trail when a large change in direction was required, the crew could rotate the M102 around its circular firing platform.
The roller-tire assembly at the rear of the trail was a major part of that system.
What This Item Is and Does
Part number 8427021 is the metal Drum, Roller Assembly used within the M102's rear roller-tire system.
The drum is positioned longitudinally beneath the rear portion of the box trail. A separate tire fits around the drum, allowing the rear of the howitzer to roll across the ground as the carriage rotates around the firing platform.
The Army Field Artillery School's original Figure 4-18 shows the complete roller-tire drive train and identifies:
- Traversing handwheel
- Bevel gears
- Flexible shaft
- Connecting shaft
- Universal joints
- Helical gears
- Axle
- Roller tire
- Box trail
- Roller tire supports
Turning the traversing handwheel transfers motion through this shaft-and-gear system to the rear roller. This allows a crewman to make directional changes while the firing platform remains the pivot point of the emplaced weapon.
The M102 Roller-Tire System
The M102's unusual rear roller replaced the traditional trail spades found on many earlier field howitzers.
When the weapon was prepared for firing, its circular firing platform was lowered and secured to the ground. The wheels were then raised, leaving the firing platform as the main pivot point.
The rear roller supported the trail as the howitzer was traversed. This arrangement allowed the M102 to cover a full 360 degrees, or 6,400 mils, without repeatedly repositioning the entire carriage. The Army's Figure 4-18 specifically shows the roller tire as part of the handwheel-driven traversing system.
Related M102 Components
The identification of P/N 8427021 is reinforced by other cataloged components from the same roller assembly.
The separate roller tire, P/N 8427019, is cataloged under NSN 2610-00-738-4278 and carries U.S. Army design-control CAGE 19204. The related hub, P/N 8427023, is cataloged under NSN 3040-00-738-4280 and is specifically identified for the M102 howitzer.
These are separate components and should not be assumed to be included with the drum unless shown or specifically stated.
Key Features
- Official nomenclature: Drum, Roller Assembly
- Army drawing/part number: 8427021
- Original FSN: 1015-738-4279
- Modern NSN: 1015-00-738-4279
- NIIN: 00-738-4279
- Federal Supply Class: 1015
- Design authority: U.S. Army
- CAGE: 19204
- Vehicle/weapon application: M102 105mm Light Towed Howitzer
- Location: Rear of the M102 box trail
- System: Roller-tire / traversing system
- Function: Core/drum supporting the separate rear roller tire
- Related tire: P/N 8427019
- Related hub: P/N 8427023
- Item type: Gun-carriage component
- Ammunition: No
Federal catalog records list the NSN as DRUM, ROLLER ASSEMBL and identify 8427021 / CAGE 19204 as the design-control reference.
Why This Item Matters
The roller assembly is one of the mechanical features that made the M102 very different from the World War II-era M101A1 it replaced.
Its ability to rotate rapidly through 360 degrees was especially valuable at Vietnam-era firebases, where artillery crews might receive missions from almost any direction.
Parts from this system are also much less recognizable when separated from the complete howitzer. The 8427021 part number and corresponding NSN provide strong identification for restoration and historical-reference purposes.
For an M102 restoration, this is a vehicle-specific carriage component connected directly to one of the weapon's most important design features.
About This Item
This listing is for one M102 Drum, Roller Assembly, P/N 8427021.
The separate roller tire, hub, axle, supports, drive shafts, gears, firing platform, trail, and complete M102 howitzer are not included unless specifically shown or stated.
Federal packaging data for NSN 1015-00-738-4279 lists a unit pack size of approximately 24.7" x 12.5" x 12.5" with a packed weight of approximately 29.7 lbs. These are packaging figures and should not be treated as the exact bare dimensions or weight of the drum itself.
Military surplus examples may show scratches, worn finish, oxidation, grease, staining, surface rust, storage marks, or other signs of age and service.
Ideal For
- M102 105mm howitzer restorations
- Vietnam War artillery collections
- U.S. Army field-artillery displays
- M102 carriage restorations
- M102 traversing-system displays
- Cold War artillery collections
- Military museums
- Gun-carriage component collections
- Technical-reference collections
- Educational artillery displays
Approx length 25", Approx width 12", Approx height 12", Approx weight 26 lbs.
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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