This is the second in a two part series by Weapons Grade author David Hambling on weapons that drill and scrape their way through targets. Check out part one here.The Pentagon is developing a bunker buster that can burrow into the ground and break up rock far more efficiently than existing rounds. But hitting underground lairs isn't the only thing the technology can do. David Burns, program manager of this "Deep Digger" bunker buster, mentioned that a breaching device based on his weapon was already being investigated. Like the Deep Digger, this will fire a volley of projectiles, creating a man-sized hole in walls. Today, you need hand-emplaced explosives or heavy weapons to get the job done. The Deep Digger-ish breaching device would have more fine control -- cutting progressively through the several feet of concrete, or breaking through a single layer of brick without demolishing the building.Another option would be to combine the special projectile with a million-round-a-minute MetalStorm launcher for a lightweight, rapid-fire mobile system. Burns believes that this could be a distinct possibility if MetalStorm can handle the rounds. Such a weapon would be able to reduce pillboxes and strongpoints into gravel almost instantly.The special projectiles would also be useful for the traditional combat engineering tasks of demolition and creating field fortifications. And they could have humanitarian uses, too Burns suggested that a mobile Deep Digger would provide the fastest way of getting to rescuing victims buried under rubble or in mine collapses.Larger projectiles already exist. BAE Systems Advanced Technologies, Inc. (ATI), who were involved in creating Deep Digger have looked at a larger-caliber cheap version of the round for quarrying and similar uses. They have already tested a 60mm round which can pulverise 0.4 cubic metres of rock with one shot - see the picture above - and they believe that a cubic meter per shot is possible. This represents an awesomely fast and efficient means of mining and tunnelling.To bring the cost-per-shot down from dollars to pennies, ATI are talking about firing concrete projectiles from an electrothermal launch system. What this really means is a steam gun - a sort of retro-future technology not seen for a while. This seemed to be the future back in 1824 when Mr Perkins steam gun was firing 900 rounds a minute; a bit later on the Confederacy had one in the Civil War which was supposed to fire twenty-four pound projectiles and scythe down opposing ranks, but was captured without a fight. The ATI proposal should be more practical. Given an unlimited supply of cheap projectiles and the possibilities multiply for both military and civilian applications. If you want to build a new metro much faster than standard tunnel boring machines, or dig an underground bunker complex in a hurry, this could be for you.Of course, if such digging device proliferate, they could end up in the wrong hands. I'm thinking of Clint Eastwood in Thunderbolt and Lightfoot, where he plays a robber whose signature is using a 20mm Oerlikon cannon to break into bank vaults. With projectile-based excavation, Thunderbolt could try his luck with Fort Knox.More seriously, this technology means that reinforced concrete cannot necessarily be relied on to protect strategic assets in the long term. Conventional weapons will be able to even threaten facilities that were built to withstand nuclear attack.-- David Hambling
© Copyright 2019 Military.com. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.