Having already fought against the Taliban in his two years in the Afghan army, Gul Mohammad has little trouble picking up the tricks of his new American-issue automatic weapon.

What concerns the young soldier is whether he will be able to rely on the weapon when it counts, as he has done so often before with its Russian equivalent, a Kalashnikov AK-47, favoured in central Asia for decades.

"The worst thing for a soldier would be if his gun were to fail in the middle of a battle," says Mohammad, speaking during a break in weapons training at the base of his 205 Atal (Hero) army corps in southern Kandahar province.

The corps numbers about 20,000 soldiers drawn from across the country to fight the fierce Taliban in their heartland -- the four provinces of the rugged south, one of the most intense battlefields of the extremist insurgency.

In a hangar at Camp Hero, 50-60 troops have been split into small groups, each with a former US Marine or army soldier introducing them to M-16 rifles and M-249 light machine guns, standard-issue weapons in most NATO countries.

After driving out the Taliban regime in late 2001, the United States started to build Afghanistan a new army to replace the illegal militia forces loyal to regional warlords who were ruling the country from different power bases.

The country's previous army had been formed during the 1979-89 Soviet occupation into a force of around 200,000 men.

But it was destroyed in the 1992-96 civil war when various ethnic-based factions -- armed and funded by the United States, Pakistan and other nations to fight the Soviets -- turned on each other.

The new Afghan army brings together young men of the country's seven ethnicities in a test of national unity.

With mainly US funding and training it now numbers roughly 80,000 men with plans for its expansion to 134,000 by 2012 -- a priority in efforts to beat the Taliban insurgency that last year was at its most intense yet.

The US military has regularly praised the progress of the new Afghan army, although critics question the loyalty of the troops, a significant AWOL rate and the lack of quality leadership.

The army started leading some anti-insurgent military operations early last year, but US and NATO troops still control most of the action.

"Leading independent operations indicate that we have improved," says the commander of 205 Atal, General Sher Mohammad Zazai.

"Our enemies are no longer able to confront us face-to-face. When we go into an area, the enemy leaves that area. If he chooses to fight us, they suffer casualties."

A programme launched in late 2007 aims to replace the AK-47s with US-made rifles and machine guns, and supply the Afghan forces with Humvees, the main vehicle used by the US military.

This means the Afghan army will get around 104,000 M-16 rifles, 4,300 machine guns, 2,250 grenade launchers, 4,000 armoured Humvees and 660 Humvee ambulances, says Lieutenant Colonel Christian Kubik, spokesman for the US military training programme.

Most of the M-16s are refurbished Marine Corps weapons and about 2,200 were donated by the Canadian government, he says.

The total cost for these weapons alone is about 60 million dollars, with the Humvees costing about 760 million dollars, he says.

The Afghan government had requested the M-16s, which are considered more accurate and reliable than the AK-47s, Kubik says.

The M-16 "provides a well-trained Afghan soldier a distinct advantage over an insurgent with an AK-47 of dubious origination," he says.

This news should reassure Mohammad, the soldier getting the hang of his new weapon, who says he takes pride in being part of the developing army.

"I have fought countless battles with Taliban," says the ethnic Hazara at Camp Hero, which is in a Pashtun area.

"They are good fighters, but we are even better," he says.

"I think I'm doing the right thing, defending my people and my country."