UPDATE 1-AIRSHOW-ATK says affordability focus paying off

* Strong demand boosts armaments sales

* Focus on low-cost weapons, rapid fielding (adds details, byline)

By Andrea Shalal-Esa

PARIS, June 15, June 15 (Reuters) - Alliant Techsystems Inc (ATK.N) on Monday said its focus on building lower-cost weapons that can be rapidly fielded is paying off with the U.S. military at a time when big-ticket programs with long development cycles are under mounting budget pressure.

ATK, which boosted revenues by 10 percent to $4.6 billion in the 2009 fiscal year ended March 31, is a smaller defense company whose stock surged to over $90 last week from $60 in late March.

It raised its fiscal 2010 sales guidance in May to a range of $4.73 billion to $4.80 billion, up from previous expectations of $4.55 billion to $4.65 billion.

"We continue to surprise ourselves," he said in an interview at the Paris Air Show.

ATK Chief Executive Dan Murphy told Reuters he was focused on using current technologies to add capabilities to current weapons and develop new ones that would get into the hands of soldiers in months, not years.

Murphy said has been telling investors since 2004 that U.S. defense spending would shift to extending the life and expanding the capabilities of existing weapons, contracts that ATK has aggressively pursued.