<SUBMISSION>
<ACCESSION-NUMBER>0001181431-03-027873
<TYPE>4/A
<PUBLIC-DOCUMENT-COUNT>2
<PERIOD>20031013
<FILING-DATE>20031029
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>AMERICAN PACIFIC CORP
<CIK>0000350832
<ASSIGNED-SIC>2810
<IRS-NUMBER>596490478
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>0930
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>3770 HOWARD HUGHES PKWY STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
<PHONE>7027352200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3770 HOWARD HUGHES PKWY STE 300
<STREET2>3770 HOWARD HUGHES PKWY STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>GIBSON JOHN R
<CIK>0001267778
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4/A
<ACT>34
<FILE-NUMBER>001-08137
<FILM-NUMBER>03962986
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>3770 HOWARD HUGHES PKWY STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
<PHONE>7027352200
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>3770 HOWARD HUGHES PKWY STE 300
<CITY>LAS VEGAS
<STATE>NV
<ZIP>89109
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>rrd20948.xml
<DESCRIPTION>OCTOBER 2003 FORM 4/AMENDED
<TEXT>
<XML>
<?xml version="1.0"?><ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4/A</documentType><periodOfReport>2003-10-13</periodOfReport><dateOfOriginalSubmission>2003-10-23</dateOfOriginalSubmission><notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000350832</issuerCik>
        <issuerName>AMERICAN PACIFIC CORP</issuerName>
        <issuerTradingSymbol>apfc</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001267778</rptOwnerCik>
            <rptOwnerName>GIBSON JOHN R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3770 HOWARD HUGHES PARKWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 300</rptOwnerStreet2>
            <rptOwnerCity>LAS VEGAS</rptOwnerCity>
            <rptOwnerState>NV</rptOwnerState>
            <rptOwnerZipCode>89109</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>CEO Chairman &amp; President</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F3"/></transactionCoding><transactionAmounts><transactionShares><value>50000</value></transactionShares><transactionPricePerShare><value>7.125</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>111937</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F3"/></transactionCoding><transactionAmounts><transactionShares><value>50000</value></transactionShares><transactionPricePerShare><value>4.87</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>161937</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>100000</value></transactionShares><transactionPricePerShare><value>9.425</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>61937</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3198</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>See Footnote.</value><footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>7.125</value></conversionOrExercisePrice><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>25000</value></transactionShares><transactionPricePerShare><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1999-07-08</value></exerciseDate><expirationDate><value>2004-07-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>7.125</value></conversionOrExercisePrice><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>25000</value></transactionShares><transactionPricePerShare><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2000-07-08</value></exerciseDate><expirationDate><value>2005-07-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>4.87</value></conversionOrExercisePrice><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>25000</value></transactionShares><transactionPricePerShare><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2001-04-24</value></exerciseDate><expirationDate><value>2011-04-24</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>4.87</value></conversionOrExercisePrice><transactionDate><value>2003-10-13</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>X</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>25000</value></transactionShares><transactionPricePerShare><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2002-04-24</value></exerciseDate><expirationDate><value>2011-04-24</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>7.781</value></conversionOrExercisePrice><exerciseDate><value>1999-09-14</value></exerciseDate><expirationDate><value>2004-09-14</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>22500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>22500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>7.781</value></conversionOrExercisePrice><exerciseDate><value>2000-09-14</value></exerciseDate><expirationDate><value>2005-09-14</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>22500</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>22500</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>8.30</value></conversionOrExercisePrice><exerciseDate><value>2002-12-13</value></exerciseDate><expirationDate><value>2012-12-13</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Options to Purchase</value></securityTitle><conversionOrExercisePrice><value>8.30</value></conversionOrExercisePrice><exerciseDate><value>2003-12-13</value></exerciseDate><expirationDate><value>2012-12-13</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>25000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">For the benefit of the Reporting Person.  Shares are held by an Institutional Fiduciary in the American Pacific Corporation Qualified Section 401(k) Plan.</footnote><footnote id="F2">Omitted in accordance with General Instructions for Form 4, Rule 4(c)(iii).</footnote><footnote id="F3">This Form 4 is being amended to correct these Transaction Codes from "P -Open Market Purchase" to "M - Exercise of Derivative Security".</footnote></footnotes><remarks>ADDITIONAL AMENDMENTS TO FORM:

Item 3. - Date of Earliest Transaction was changed from 10/23/2003 to 10/13/2003 to correct a typographical error.

The first Transaction previously reported on Table II has been removed in its entirety as it was reported in error.</remarks><ownerSignature><signatureName>David N. Keys, attorney-in-fact</signatureName><signatureDate>2003-10-29</signatureDate></ownerSignature></ownershipDocument>



</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24.1
<SEQUENCE>3
<FILENAME>rrd12801_14707.htm
<DESCRIPTION>POWER OF ATTORNEY
<TEXT>
<HTML>
<HEAD>
<TITLE>
rrd12801_14707.html
</TITLE>
</HEAD>
<BODY>
<PRE>
POWER OF ATTORNEY
     Know all by these presents, that the undersigned hereby constitutes and appoints
each of John R. Gibson and David N. Keys, signing singly, the undersigned's true and
lawful attorney-in-fact to:
     1.	execute for and on behalf of the undersigned, in the undersigned's capacity as
an officer and/or director of American Pacific Corporation, a Delaware corporation (the
"Company"), Forms 3, 4, and 5 in accordance with Section 16(a) of the Securities
Exchange Act of 1934 and the rules thereunder;
     2.	do and perform any and all acts for and on behalf of the undersigned that may
be necessary or desirable to complete and execute any such Form 3, 4, or 5, complete and
execute any amendment or amendments thereto, and timely file such form with the
United States Securities and Exchange Commission and any stock exchange or similar
authority; and
     3.	take any other action of any type whatsoever in connection with the foregoing
which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of,
or legally required by, the undersigned, it being understood that the documents executed
by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney
shall be in such form and shall contain such terms and conditions as such attorney-in-fact
may approve in such attorney-in-fact's discretion.
     The undersigned hereby grants to each such attorney-in-fact full power and
authority to do and perform any and every act and thing whatsoever requisite, necessary,
or proper to be done in the exercise of any of the rights and powers herein granted, as
fully to all intents and purposes as the undersigned might or could do if personally
present, with full power of substitution or revocation, hereby ratifying and confirming all
that such attorney-in-fact, or such attorney-in-fact's substitute or substitutes, shall
lawfully do or cause to be done by virtue of this power of attorney and the rights and
powers herein granted.  The undersigned acknowledges that the foregoing attorneys-in-
fact, in serving in such capacity at the request of the undersigned, are not assuming, nor is
the Company assuming, any of the undersigned's responsibilities to comply with Section
16 of the Securities Exchange Act of 1934.
     This Power of Attorney shall remain in full force and effect until the undersigned is
no longer required to file Forms 3, 4, and 5 with respect to the undersigned's holdings of
and transactions in securities issued by the Company, unless earlier revoked by the
undersigned in a signed writing delivered to the foregoing attorneys-in-fact.
     IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to
be executed as of this 30th  day of September, 2002.

     Signature: 	    /s/ JOHN R. GIBSON
	John R. Gibson

</PRE>
</BODY>
</HTML>

</TEXT>
</DOCUMENT>
</SUBMISSION>
