X0306 4 2013-10-01 0 0000866121 ALLIANT TECHSYSTEMS INC ATK 0001369308 Chaplin Scott David ALLIANT TECHSYSTEMS INC. 1300 WILSON BOULEVARD ARLINGTON VA 22209 0 1 0 0 SVP, General Counsel & Secy Common Stock 2013-10-01 4 F 0 191 0 D 4733 D Shares withheld to pay taxes applicable to the vesting of restricted stock. 4,347 of these shares are subject to certain restrictions including possible forfeiture applicable to restricted stock issued under the Issuer's 2005 Stock Incentive Plan. /s/Scott D. Chaplin 2013-10-02