<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-08-12</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000009389</issuerCik>
        <issuerName>BALL CORP</issuerName>
        <issuerTradingSymbol>BLL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001205948</rptOwnerCik>
            <rptOwnerName>WESTERLUND DAVID A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>BALL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>10 LONGS PEAK DR.</rptOwnerStreet2>
            <rptOwnerCity>BROOMFIELD</rptOwnerCity>
            <rptOwnerState>CO</rptOwnerState>
            <rptOwnerZipCode>80021-2510</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SR VP, ADMIN &amp; CORP SECRETARY</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Prepaid Variable Forward Contract</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-08-12</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20576</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2007-08-10</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2007-08-10</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>20576</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>20576</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">On 8-12-04, Ann B. Westerlund (Seller), an affiliate of David A. Westerlund, entered into a prepaid variable forward contract (Contract) with a broker/dealer (Buyer) for disposition of 20,576 shares of Ball Corp Common Stock (Ball Shares). Contract obligates Seller to deliver to Buyer on 8-10-07 (Settlement Date) a number of Ball Shares equal to $1,486,821.76 (20,576 Ball Shares @$72.26). In exchange Seller initially receives 86.34% of $1,486,821.76 ($62.39/share Purchase Price). Per Contract on Settlement Date, Seller receives up to 120% of $72.26/share price ($86.72/share Ceiling Price) if Ball Shares appreciate above $72.26/share (Floor Price). Ball Shares to be sold by Seller under Contract will be 20,576 base amount &amp; will depend on whether the Ceiling Price is above Floor Price. Buyer received Ball Shares but they will not be sold until 8-10-07. At Seller's option she may deliver cash equivalent to value of required number of Ball Shares to be delivered on Settlement Date.</footnote>
    </footnotes>

    <remarks>Total number of Common Shares directly owned includes shares acquired through the Ball Corporation Dividend Reinvestment Plan.  Total number of Common Shares directly owned includes shares acquired through participation in the Ball Corporation Employee Stock Purchase Plan.  Total number of 401(k) Plan shares includes shares acquired through periodic dividend reinvestment and employer matching contributions.</remarks>

    <ownerSignature>
        <signatureName>By: Charles E. Baker, GenCounsel&amp;AsstCorpSec  For: David A. Westerlund</signatureName>
        <signatureDate>2004-08-13</signatureDate>
    </ownerSignature>
</ownershipDocument>

