Canadian army gunners in Afghanistan are now cleared to fire new GPS-guided artillery shells at Taliban militants at a cost of $150,000 a round.

A Canadian M777 howitzer firing at Sperwan Ghar, Afghanistan.
(Master Cpl. Yves Gemus/Canadian Forces)

The Excalibur shell could be the most expensive conventional ammunition ever fired by the military.

Supporters argue that the weapon, which has the ability to correct itself in flight, has pinpoint accuracy. They predict that will cut down on the mounting civilian death toll from air strikes in a war-torn region where insurgents often hide among the population.

"It lands exactly where you want it to land," said Lt.-Col. Jim Willis, a senior officer in charge of acquiring the munitions. "It provides more safety."

About 18 months ago, the army announced its intention to buy a handful of the experimental shells to go along with its new 155-millimetre M777 howitzers.

Introducing the weapon to the army's arsenal has been slower than expected because of concerns related to the shell's performance in cold weather and precautions to make sure the GPS signals can't be jammed or scrambled by insurgents.

Willis said battery guns supporting Canada's battle group in Kandahar recently test-fired the shell in the desert and the new weapon performed flawlessly. He wouldn't say how many shells were fired.

The XM982 shell has a GPS receiver, guidance unit and winglets to steer to the target.
(Raytheon Missile Systems/Department of National Defence)

A U.S. army unit in eastern Afghanistan conducted its own tests late last month and has also cleared the Excalibur for action.

The price tag has provided fodder for critics of the war, who've described the shell as overkill and noted that the cost is like firing a Ferrari. (The manufacturer's suggested retail price of a two-passenger 2008 Ferrari F430 starts at about $187,000.)

U.S. defence contractor Raytheon began promoting the shells in the fall of 2006 as the "next generation" of artillery munitions.

Willis, an officer with 32 years experience with big guns, said he believes the Excalibur represents a quantum leap forward because instead of firing a dozen shells at one target, only one round is needed.

The Defence Department spent $150,000 a round in the fall of 2006 on the first batch of shells off the production line. Willis says the cost is expected to drop to $86,000 a shell as time goes on.

Ordinary high-explosive rounds cost up to $2,000 apiece.

The Excalibur shell uses satellite signals and software to guide it to within 10 metres of its intended target, even when fired from up to 40 kilometres away. Regular shells are said to be accurate to within 50 metres.

Willis conceded that army planners have noticed a difference in performance during freezing temperatures, but added that the shell is being used in hot weather in Afghanistan.

The question of whether the Excalibur has been led astray by sophisticated interference technology was something both the army and defence industry officials were reluctant to address.

Safeguards are in place to make sure a round doesn't land among friendly troops or in the midst of civilians, Willis said.

The system "has countermeasures built in, but obviously I can't get into the details here," he said.

"Aside from the countermeasures, it flies so quickly to a target that the chance of it being jammed is remote."