GenCorp Inc. Amended and Restated 2013 Employee Stock Purchase Plan Approved by Shareholders on March 27, 2013 and as amended by the Board of Directors on January 21, 2014 and as last amended by the Board of Directors on July 24, 2014 GENCORP INC. 2013 EMPLOYEE STOCK PURCHASE PLAN

The purpose of this Plan is to provide an opportunity for Employees of GenCorp Inc. (the “Corporation”) and its Designated Affiliates to purchase Common Stock of the Corporation and thereby to have an additional incentive to contribute to the prosperity of the Corporation. It is the intention of the Corporation that the Plan qualify as an “Employee Stock Purchase Plan” under Section 423 of the Internal Revenue Code of 1986, as amended, although the Corporation makes no undertaking nor representation to maintain such qualification. In addition, this Plan document authorizes the grant of options under a non-423 Plan which do not qualify under Section 423 of the Code pursuant to rules, procedures or sub-plans adopted by the Board (or its designate) designed to achieve desired tax or other objectives.

timing of Offering Periods may be changed or modified by the Committee.

Any Employee regularly employed on a full-time or part-time (20 hours or more per week on a regular schedule) basis, or on any other basis as determined by the Corporation (if required under applicable local law) for purposes of the Non-423 Plan or any separate offering under the Code Section 423 Plan, by the Corporation or by any Designated Affiliate on an Entry Date shall be eligible to participate in the Plan with respect to the Offering Period commencing on such Entry Date, provided that the Committee may establish administrative rules requiring that employment commence some minimum period (e.g., one pay period) prior to an Entry Date to be eligible to participate with respect to the Offering Period beginning on that Entry Date. The Committee may also determine that a designated group of highly compensated Employees are ineligible to participate in the Plan so long as the excluded category fits within the definition of “highly compensated employee” in Code Section 414(q). No Employee may participate in the Plan if immediately after an option is granted the Employee owns or is considered to own (within the meaning of Code Section 424(d)) shares of stock, including stock which the Employee may purchase by conversion of convertible securities or under outstanding options granted by the Corporation, possessing five percent (5%) or more of the total combined voting power or value of all classes of stock of the Corporation or of any of its Subsidiaries. All Employees who participate in the same offering under the Plan shall have the same rights and privileges under such offering, except for differences that may be needed to facilitate compliance with applicable local law, as determined by the Corporation and that are consistent with Code Section 423(b)(5); provided, however, that Employees participating in the Non-423 Plan by means of rules, procedures or sub-plans adopted pursuant to Section 15 need not have the same rights and privileges as Employees participating in the Code Section 423 Plan. The Board may impose restrictions on eligibility and participation of Employees who are officers and directors to facilitate compliance with federal or state securities laws or foreign laws.

If a Participant receives a hardship distribution from the Corporation’s or a Designated Affiliate’s qualified cash or deferred arrangement, such Participant shall cease participation in the Plan and shall be unable to resume participation in the Plan until the later of six months from the date of the hardship distribution or such later date as provided in the Corporation’s or a Designated Affiliate’s qualified cash or deferred arrangement.

The Plan shall be implemented by consecutive Offering Periods with a new Offering Period commencing on the first Trading Day on or after January 1 and July 1 of each year, or on such other date as the Committee shall determine, and continuing thereafter for six (6) months or until terminated pursuant to Section 13 hereof. The Committee shall have the authority to change the duration of Offering Periods (including the commencement dates thereof) with respect to future offerings without Shareowner approval if such change is announced at least five (5) days prior to the scheduled beginning of the first Offering Period to be affected thereafter.

Employee’s Compensation, not to exceed ten percent (10%) of the Employee’s Compensation. All payroll deductions may be held by the Corporation and commingled with its other corporate funds where administratively appropriate, except where applicable local law requires that Contributions to the Plan from Participants be segregated from the general corporate funds and/or deposited with an independent third party. No interest shall be paid or credited to the Participant with respect to such Contributions, unless required by local law. The Corporation shall maintain a separate bookkeeping account for each Participant under the Plan and the amount of each Participant’s Contributions shall be credited to such account. A Participant may not make any additional payments into such account.

In the event any Participant terminates employment with the Corporation or any of its Designated Affiliates for any reason (including death) prior to the expiration of an Offering Period, the Participant’s participation in the Plan shall terminate and all amounts credited to the Participant’s account shall be paid to the Participant or, in the case of death, to the Participant’s heirs or estate, without interest. Whether a termination of employment has occurred shall be determined by the Committee (subject to any post-employment participation period required by law). The Committee may also establish rules regarding when leaves of absence or changes of employment status will be considered to be a termination of employment, including rules regarding transfer of employment among Designated Affiliates, Affiliates and the Corporation, and the Committee may establish termination-of-employment procedures for this Plan that are independent of similar rules established under other benefit plans of the Corporation and its Affiliates.

an option is “granted” on a Participant’s Entry Date. An option will expire upon the earlier to occur of (i) the termination of a Participant’s participation in the Plan; or (ii) the termination of an Offering Period. This section shall be interpreted so as to comply with Code Section 423(b)(8). To the extent permissible under Code Section 423 and the regulations thereunder, any amounts that remain in the Participant’s Account because of a share limitation shall be carried over to the next Offering Period.

Upon the expiration of each Offering Period, a Participant’s option shall be exercised automatically for the purchase of that number of whole shares of Common Stock which the accumulated Contributions credited to the Participant’s account at that time shall purchase at the applicable Purchase Price. Any amounts that remain in the Participant’s Account shall be carried over to the next Offering Period. Notwithstanding the foregoing, the Corporation or its designee may make such provisions and take such action as it deems necessary or appropriate for the withholding of taxes and/or social insurance contributions which the Corporation or its Designated Affiliate is required or permitted by applicable law or regulation of any governmental authority to withhold. Each Participant, however, shall be responsible for payment of all individual tax and social insurance contribution liabilities arising under the Plan.

As soon as practicable after the exercise of an option, the Corporation shall deliver to the Participant a record of the Common Stock purchased and the balance of any amount of Contributions credited to the Participant’s account not used for the purchase, except as specified below. The Committee may permit or require that shares be deposited directly with a broker designated by the Committee or to a designated agent of the Corporation, and the Committee may utilize electronic or automated methods of share transfer. The shares shall be retained with such broker or agent for a thirty (30) day period of time or such longer period of time as may be required by the Committee. The Committee may establish other procedures to permit tracking of disqualifying dispositions of such shares. The Corporation shall retain the amount of payroll deductions used to purchase Common Stock as full payment for the Common Stock and the Common Stock shall then be fully paid and non-assessable. Except as otherwise provided herein, no Participant shall have any voting, dividend, or other Shareowner rights with respect to shares subject to any option granted under the Plan until the shares subject to the option have been purchased and delivered to the Participant as provided in this Section 9.

If after the grant of an option, but prior to the purchase of Common Stock under the option, there is any increase or decrease in the number of outstanding shares of Common Stock because of a stock split, stock dividend, combination or recapitalization of shares subject to options, the number of shares to be purchased pursuant to an option, the price per share of Common Stock covered by an option and the maximum number of shares specified in Section 7.1 may be appropriately adjusted by the Board, and the Board shall take any further actions which, in the exercise of its discretion, may be necessary or appropriate under the circumstances.

The Board’s determinations under this Section 10 shall be conclusive and binding on all parties.

In the event of the proposed liquidation or dissolution of the Corporation, the Offering Period will terminate immediately prior to the consummation of such proposed transaction, unless otherwise provided by the Board in its sole discretion, and all outstanding options shall automatically terminate and the amounts of all payroll deductions will be refunded without interest (except as may be required by applicable local law, as determined by the Corporation) to the Participants.

In the event of a proposed sale of all or substantially all of the assets of the Corporation, or the merger or consolidation of the Corporation with or into another corporation, then in the sole discretion of the Board, (1) each option shall be assumed or an equivalent option shall be substituted by the successor corporation or parent or subsidiary of such successor corporation, (2) a

date established by the Board on or before the date of consummation of such merger, consolidation or sale shall be treated as a Purchase Date, and all outstanding options shall be exercised on such date, or (3) all outstanding options shall terminate and the accumulated Contributions will be refunded without interest to the Participants.

Options granted to Participants may not be voluntarily or involuntarily assigned, transferred, pledged, or otherwise disposed of in any way, and any attempted assignment, transfer, pledge, or other disposition shall be null and void and without effect. If a Participant in any manner attempts to transfer, assign or otherwise encumber his or her rights or interests under the Plan, other than as set forth in Section 22 and as permitted by the Code, such act shall be treated as an election by the Participant to discontinue participation in the Plan pursuant to Section 5.2.

The Board shall appoint a Committee consisting of at least two members who will serve for such period of time as the Board may specify and whom the Board may remove at any time. The Committee will have the authority and responsibility for the day-to-day administration of the Plan, the authority and responsibility specifically provided in this Plan and any additional duty, responsibility and authority delegated to the Committee by the Board, which may include any of the functions assigned to the Board in this Plan. The Committee may delegate to one or more individuals the day-to-day administration of the Plan. The Committee shall have full power and authority to promulgate any rules and regulations which it deems necessary for the proper administration of the Plan, to interpret the provisions and supervise the administration of the Plan, to make factual determinations relevant to Plan entitlements and to take all action in connection with administration of the Plan as it deems necessary or advisable, consistent with the delegation from the Board. Decisions of the Board and the Committee shall be final and binding upon all participants. Any decision reduced to writing and signed by a majority of the members of the Committee shall be fully effective as if it had been made at a meeting of the Committee duly held. The Corporation shall pay all expenses incurred in the administration of the Plan. No Board or Committee member shall be liable for any action or determination made in good faith with respect to the Plan or any option granted hereunder.

The Corporation shall not be under any obligation to issue Common Stock upon the exercise of any option unless and until the Corporation has determined that: (i) it and the Participant have taken all actions required to register the Common Stock under the U.S. Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder or to perfect an exemption from the registration requirements thereof; (ii) any applicable listing requirement of any stock exchange on which the Common Stock is listed has been satisfied; and (iii) all other applicable provisions of state, federal and applicable foreign law have been satisfied.

This Plan and the Corporation’s obligation to sell and deliver shares of its stock under the Plan shall be subject to the approval of any governmental authority required in connection with the Plan or the authorization, issuance, sale, or delivery of stock hereunder.

Nothing contained in this Plan shall be deemed to give any Employee the right to be retained in the employ or service of the Corporation or any Designated Affiliate or to interfere with the right of the Corporation or Designated Affiliate to discharge any Employee at any time.

This Plan shall be governed by the laws of the State of Delaware, U.S.A., without regard to that State’s choice of law rules.

20    EFFECTIVE DATE.

This Plan shall be effective January 1, 2014, subject to approval of the Shareowners of the Corporation within 12 months before or after its adoption by the Board.

Individual accounts shall be maintained for each Participant in the Plan. Statements of account shall be given to Participants at least annually, which statements shall set forth the amounts of Contributions, the Purchase Price, the number of shares purchased and the remaining cash balance, if any. The Committee shall also file the appropriate reports with the IRS required under Code Section 6039(a) and provide the statements to Participants required under Code Section 6039(b).

Each Participant under the Plan may, from time to time, name any beneficiary or beneficiaries (who may be named contingently or successively) to whom any benefit under the Plan is to be paid in case of his or her death before he or she receives any or all of such benefit. Each such designation shall revoke all prior designations by the same Participant, shall be in a form prescribed by the Committee, and will be effective only when filed by the Participant in writing with the Corporation during the Participant’s lifetime. In the absence of any such designation, benefits remaining unpaid at the Participant’s death shall be paid to the Participant’s estate.