Original URL: http://www.theregister.co.uk/2010/10/15/xm25_and_exacto/

Futuristic Judge Dredd smartguns issued to 101st Airborne

Also: Target-seeking sniper bullets move to Phase II

By Lewis Page

Posted in Science, 15th October 2010 15:17 GMT

It's all go in the world of futuristic Judge Dredd style guns today. Reports suggest that a battalion of US airmobile* troops in Afghanistan are to be equipped with the XM-25 computing smart-rifle, able to strike enemies hiding round corners or in trenches. A successful "proof of concept" of a guided homing bullet for use in sniper rifles has also been announced.

A soldier aims an XM-25 smartgun. Credit: PEO Soldier

Trench warfare finally made obsolete

First up is the XM-25, which we've covered on these pages before. The Soldier Systems blog quotes Colonel Doug Tamilio of the US Army's personal-kit office as stating that a battalion of the 101st Airborne* will receive the new weapon starting next month.

The XM-25 shoots a heavy 25mm exploding slug, whose precision time fuse is set by the gun's systems at the moment of being fired. The weapon's computing sight measures the distance to the target precisely using a laser, and corrects automatically for such factors as air pressure, temperature, relative elevation etc. Buttons above the trigger allow the point at which the shells will detonate to be moved nearer or further away.

All this allows a soldier to make his XM-25 smartshells explode in midair exactly where he wants them to. This can be used to spray deadly shrapnel into an enemy hiding around a corner, or one lurking behind a wall, in a trench etc - or to make a round explode in the middle of a target room or cave.

Apart from basic high-explosive frag rounds, the US Army plans to offer a Dredd-like array of alternative XM-25 smartshells. There will be a shaped armour penetrator, a flash-bang stun warhead and a door-breacher. There's also to be an "anti personnel" round: in the US military that normally means an artillery shell which throws a cloud of smaller projectiles - either metal balls ("canister") or finned darts ("flechette" or "beehive"). The XM-25 version could function like a shotgun, simply throwing the shot or flechettes out of the end of the barrel for maximum closeup firepower, or it could use the gun's airburst capability and deliver a spread of projectiles at long range.

According to Tamilio, the existing five prototype weapons will be issued to the 101st to start with, then replaced by 36 newly-ordered ones. There will be plenty of 25mm smartshell ammo. The idea would not be to equip every soldier in a given unit with the smartgun - rather it would be a specialist weapon, like a light machinegun. The numbers suggest that it would be issued to one man in each rifle squad of eight.

Of course as everyone knows, Judge Dredd - in addition to high explosive and many other kinds of bullet - would occasionally fire homing heatseeker rounds from his Lawgiver sidearm.

That's not quite on offer yet, but something nearly as good is. Our old friends at the Pentagon mad-scientist asylum have been working for some time on a project they call EXtreme ACcuracy Tasked Ordnance (EXACTO), which aims to produce a .50-calibre bullet which would be shot out of a gunbarrel just like a normal dumb slug - but would then be able to steer itself onto a bright dot produced by a targeting laser.

A .50-calibre round can easily fly more than 7 kilometres (4.3 miles), but even the best, most accurate snipers can't score hits at anything like such ranges: beyond say 2,500m the difficulties of aiming and compensation for environmental effects become insurmountable.

But an EXACTO slug would potentially be able to exploit the full ballistic potential of .50-calibre cartridges. Snipers armed with existing heavy rifles could potentially pick off targets four or five miles away with a single shot - and these targets could be moving unpredictably as well, as it would be easy to hold a laser dot on them.

In an announcement issued yesterday, DARPA says:

The program recently completed its first phase by achieving a successful proof of concept with a high fidelity hardware-in-the-loop (HITL) simulation. Phase II will build and test a complete system, including the required optical sighting equipment and guided .50 caliber projectiles.

The Pentagon warboffins add intriguingly that "although intended for use by snipers, this technology is directly applicable to larger calibers as well as vehicle, ship- and airborne-mounted systems".

This last raises the possibility that EXACTO rounds might not be shot only from heavy sniper rifles like the US Army's M107. Most obviously, .50-calibre heavy machine guns might pour out streams of EXACTO smartslugs, all of which would then hammer accurately into a small area - if necessary curving their flight on the way to remorselessly home on a moving target.

It's probably at least a few years yet, though, until EXACTO reaches the field by the sound of it - if it ever does. Most DARPA projects end in failure. The related "One Shot" Terry Pratchett effect** computer-gunscope project is nearer to completion.

For now, though - if Colonel Tamilio is right and the XM-25 really is finally going into combat - it would seem that the wouldbe Judge Dredds of the US military will have to be satisfied with the kills-round-corners exploding bullet smartgun. ®

Bootnote

*The 101st's title might suggest to some readers that it is a parachute unit like the 82nd Airborne. It used to be, but nowadays it's a helicopter-borne (Airmobile/Air-Assault) formation.

**It makes million-to-one shots hit nine times out of 10. Well, six actually, if you want to get picky.