* Obama to sign weapons reform bill Friday

* Bill requires more pre-production testing of weapons

* House panel investigating other possible reforms (Adds Obama to sign bill Friday)

By Andrea Shalal-Esa

WASHINGTON, May 21 (Reuters) - The U.S. House of Representatives unanimously approved legislation on Thursday to reform the way the Pentagon buys weapons, sending it to President Barack Obama to be signed into law.

The House voted 411-0 to approve compromise legislation hammered out by negotiators on Tuesday. The bill was approved unanimously by the Senate on Wednesday night.

Obama, who has criticized cost overruns and schedule delays in major weapons programs, will sign the bill on Friday, the White House said.

House Armed Services Committee Chairman Ike Skelton said the bill won broad support in Congress because weapons program cost overruns and schedule delays were rampant.

The Government Accountability Office estimated nearly 70 percent of the Pentagon's 96 biggest weapons programs were over budget in 2008, with cost growth alone amounting to $296 billion.