X0306 4 2013-05-14 0 0000866121 ALLIANT TECHSYSTEMS INC ATK 0001313857 Larson Blake E 1300 WILSON BOULEVARD, SUITE 400 ARLINGTON VA 22209 0 1 0 0 Sr VP and Pres Aerospace Group Common Stock 2013-05-14 4 A 0 1629 0 A 11697 D Common Stock 2013-05-14 4 F 0 527 76.64 D 11170 D Common Stock 19000 I By Family Trust Common Stock 631 I By Spousal Trust Common Stock 184 I By Family Trust Shares acquired represent payment of a Performance Share Award (PSA) under the 2005 Stock Incentive Plan, and shares disposed represent shares withheld from the PSA to pay withholding taxes. 4,976 of these shares are subject to certain restrictions including possible forfeiture applicable to restricted stock issued under the Issuer's 2005 Stock Incentive Plan. These shares are held in a family trust, of which the reporting person's spouse and children are the beneficiaries and the reporting person is the settlor and trustee. These shares are held in a trust of which the reporting person's spouse is the trustee and the reporting person is the beneficiary. These shares represent the reporting person's proportional interest as a beneficiary of a family trust. /s/Blake E. Larson 2013-05-16