A RIFLE capable of firing explosive bullets that can
detonate within a metre of a target could let soldiers fire on snipers
hiding in trenches, behind walls or inside buildings.
US army has developed the XM25 rifle to give its troops an alternative
to calling in artillery fire or air strikes when an enemy has taken
cover and can't be targeted by direct fire. "This is the first
leap-ahead technology for troops that we've been able to develop and
deploy," says Douglas Tamilio, the army's project manager for new weapons for soldiers. "This gives them another tool in their kitbag."
rifle's gunsight uses a laser rangefinder to calculate the exact
distance to the obstruction. The soldier can then add or subtract up to
3 metres from that distance to enable the bullets to clear the barrier
and explode above or beside the target.
As the 25-millimetre round is fired, the gunsight
sends a radio signal to a chip inside the bullet, telling it the
precise distance to the target. A spiral groove inside the barrel makes
the bullet rotate as it travels, and as it also contains a magnetic
transducer, this rotation through the Earth's magnetic field generates
an alternating current. A patent
granted to the bullet's maker, Alliant Techsystems, reveals that the
chip uses fluctuations in this current to count each revolution and, as
it knows the distance covered in one spin, it can calculate how far it
rifle would allow a soldier faced with a sniper firing from a window to
take a distance measurement to the window, add a metre, fire through
the window, and have the round detonate 1 metre inside the room. The
same method could be used to fire behind a wall or over a trench.