H&R SPIW
Harrington & Richardson · Assault Rifle · Prototype · 1964
Also known as: Harrington & Richardson SPIW, H&R Special Purpose Individual Weapon, Dardick SPIW
Overview
The H&R SPIW is an experimental American assault rifle developed by Harrington & Richardson for the United States Army's Special Purpose Individual Weapon (SPIW) program in the early 1960s. It was built around the unconventional Dardick open-chamber action, feeding polymer 'tround' cartridges that each launched three 5.6mm flechettes simultaneously, paired with an under-barrel three-shot grenade launcher. The design was judged unsafe to fire and far too heavy at roughly 10.8 kg loaded, and the US Army ruled it out in 1964.
Specifications
| Weight (empty) | 9800 g (345.7 oz) |
| Weight (loaded) | 10800 g (381.0 oz) |
| Action Type | Revolving |
| Firing Mechanism | Fixed Firing Pin |
| Magazine Capacity | 60 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 1350 m/s (4429 fps) |
| Muzzle Energy | 592 J (437 ft·lbf) |
| Effective Range | 500 m (547 yd) |
| Rate of Fire | 2000 rpm |
| Barrel Rifling | Smoothbore |
| Frame Material | Steel |
| Barrel Material | Steel |
| Finish | Parkerized |
Calibers
- 5.6mm Flechette (SPIW) · primary — also known as 5.6mm flechette, XM144 flechette, Dardick tround flechette, .22 flechette
Features
- Firing modes: Semi Automatic, Full Automatic
- Feed systems: Detachable Box Magazine, Open Chamber Tround Feed
- Features: Dardick Open Chamber Action, Triple Flechette Tround, Integrated Grenade Launcher, Smoothbore Flechette Barrel
Service history
Operators
- United States Army · as SPIW (trials)
Production
Production years: 1962-1964
Only experimental prototypes were built for the SPIW trials; no series production.
Origin
Country of origin: United States
Designer: David Dardick
Discontinued: 1964
Notes
The open revolving chamber of the Dardick action exposed the firing cycle, making the weapon dangerous to operate. Its triple-flechette trounds gave an effective projectile rate far above conventional rifles but at the cost of weight and safety.
Background
Harrington & Richardson's SPIW entry adapted David Dardick's radical open-chamber 'tround' firing system to launch clusters of tiny steel flechettes. Promising a wall of arrow-like projectiles, it instead became a cautionary tale of the SPIW program: rejected in 1964 as both unsafe to fire and impossibly heavy.