The Navy's new railgun is set to be a revolutionary weapon, which will offer an unprecedented range and rate of fire -- "turn[ing] destroyers into super-long-range machine guns," as one wag observers. But several critics believe the weapon will not be able to do enough damage to targets with the solid tungsten rounds which have been seen so far. Enter reactive materials -- so-called "explosive metals" which can produce all kinds of novel effects.
Tunsgten ammunition is fine against naval targets and vehicles. But the requirement for naval gunfire includes other targets -- like deeply-buried bunkers. “A solid slug of metal isn’t going to do much damage. It will stir up the dirt where it lands. But if you want a bigger projectile to do some damage, then you’ve got to be able to put explosives inside,” former Pentagon weapons-tester Philip Coyle tells* National Defense Magazine. *“It’s got to be more than a lead brick — it’s got to be a bomb with explosive force."
It's not easy building something explosive which can withstand the forces involved in railgun launch, however. So the Navy is researching new, reactive materials that might be able to stand up, budget documents reveal:
Continue research in technology development for the next generation reactive material warhead concepts (formulations, material properties, and energy release experiments) for highly reactive materials, high density reactive materials and novel reactive structural materials. Transition applications to specific target interaction, lethality modeling and ordnance specific experiments and demonstrations to Electromagnetic Rail Gun. (emphasis mine)
With an upgrade like this, the railgun could be able to deliver enough explosive effects to deal with hard targets like bunkers. And it might be able to tackle area targets as well: an alternative option is described as 'payload pellets' of Reactive Material, which will shower down and destoy soft targets such as vehicles in much the same way as the RM shrapnel from the BattleAxe warhead.
Since the RM is not explosive and the rounds are comparatively lightweight, future warships will have deep magazines without having to store dangerous propellant or explosive.
The technology to combine tungsten with reactive material is being developed by both Liquidmetal Technologies and Physcial Sciences Inc (working with ATK Thiokol Inc). The idea, according to a company statement, is to "enhance projectile lethality by depositing a combined kinetic and chemical energy in the target, which is greater than the corresponding kinetic energy deposited by a non-reactive tungsten munition."
[The m]aterials technology development will be of great benefit to battlefield scenarios involving electromagnetic (EM) gun munitions.
The reactive tungsten alloys will allow the Navy to develop EM gun launch packages, which achieve target levels of destructive capacity, while remaining inert at normal launch and service conditions.*Meanwhile Liquidmetal have been researching the use of their tungsten technology to replace depleted uranium penetrators used by anti-tank weapons. The reactive-enhanced tungsten may find uses in this area as well. *
The same technology can equally be applied to smaller projectiles, such as the 'Reactive Material Enhanced Bullet' developed under a quick reaction program and described in this 2004 Navy briefing:
