After years of denying allegations of lax financial oversight, the National Rifle Association has made a stunning declaration in a new tax filing: Current and former executives used the nonprofit group’s money for personal benefit and enrichment.The NRA said in the filing that it continues to review the alleged abuse of funds, as the tax-exempt organization curtails services and runs up multimillion-dollar legal bills. The assertion of impropriety comes four months after the attorney general of New York state filed a lawsuit accusing NRA chief executive Wayne LaPierre and other top officials of using NRA funds for decades to provide inflated salaries and expense accounts.