Receivers / Flats / Uppers

Receivers / Flats / Uppers

Explore our premier selection of HK receivers, flats, and uppers at HKParts, perfect for building or upgrading your Heckler & Koch firearms. Our products feature precision-engineered MP5 receiver flats, HK 416 complete upper assemblies, and a wide range of custom options designed for tactical and precision shooting. Whether you are customizing an MP5, upgrading an HK416, or constructing a new firearm, our high-quality components provide unparalleled reliability and performance.

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  • On Sale
    HK MP5 40/10 Receiver Flat - BLEMISHED HK MP5 40/10 Receiver Flat - BLEMISHED
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    HK MP5 40/10 Receiver Flat - BLEMISHED

    HKP HK Parts

    Now: $136.95
    Was: $399.95
    HK MP5 40/10 Receiver Flat - BLEMISHED ONLY 1 UNIT AVAILABLE - AS PICTURED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. The new and latest production with the...
    HKP-00767-B
    Now: $136.95
    Was: $399.95
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    Was: $399.95
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  • HK MP5, HK94 Rivet for Case Deflector and Sling - Pack of 5 HK MP5, HK94 Rivet for Case Deflector and Sling - Pack of 5
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    HK MP5, HK94 Rivet for Case Deflector and Sling - Pack of 5

    LSC

    $3.95
    LSC HK MP5, HK94 Rivet for Sling Clip and Case Deflector - Pack of 5 Each case deflector, US or German-made, will require two rivets to attach the case deflector to the receiver or flat. You will need two of these for installing one case deflector...
    HKP-99400
    $3.95
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    $3.95
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  • On Sale
    HK UMP Paddle Mag Release - Extended - BLEMISHED HK UMP Paddle Mag Release - Extended - BLEMISHED
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    HK UMP Paddle Mag Release - Extended - BLEMISHED

    HKP HK Parts

    Now: $24.95
    Was: $34.95
    HK UMP Paddle Mag Release - Extended - 9mm / .40 S&W / .45 ACP - BLEMISHED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. Billeted alloy UMP magazine release...
    HKP-17919-B
    Now: $24.95
    Was: $34.95
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    Was: $34.95
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  • HK91, G3, HK93 Anti-Rattle Mag Release HK91, G3, HK93 Anti-Rattle Mag Release
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    HK91, G3, HK93 Anti-Rattle Mag Release

    MKE

    $32.95
    MKE Anti Rattle Paddle Magazine Release Upgrade your rifle with MKE's anti-rattle style paddle mag release. Compatible With: HK G3, HK91 HK33, HK53, HK93 HK PSG1, MSG90 In-spec clones and custom builds
    HKP-99348
    $32.95
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  • HK417, MR762 Upper Receiver and Handguard - Flecktarn HK417, MR762 Upper Receiver and Handguard - Flecktarn
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    HK417, MR762 Upper Receiver and Handguard - Flecktarn

    H&K Heckler & Koch

    $1,489.95
    HK417, MR762 Upper Receiver and 13.5" Handguard - Flecktarn Factory HK MR762 matching flecktarn upper receiver and 13.5" handguard.   ONLY 3 SETS AVAILABLE AND WILL NOT BE RESTOCKED Compatible With: HK MR762 HK417  
    HKP-99325
    $1,489.95
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  • On Sale
    Used - H&K MP5 40/10 Factory Trunnion - USED - HKP-99173 HK MP5 Trunnion 10mm / .40 S&W - Factory - USED
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    HK MP5 Trunnion 10mm / .40 S&W - Factory - USED

    H&K Heckler & Koch

    Now: $297.95
    Was: $549.95
    H&K MP5 40/10 Factory Trunnion - USED ONLY 1 UNIT AVAILABLE - AS PICTURED Used genuine German trunnion with round guides. Compatible With: HK MP5 40/10 THIS CLOSEOUT PART IS NOT ELIGIBLE FOR RETURN, REFUND, OR EXCHANGE.  SALE IS FINAL.
    HKP-99173
    Now: $297.95
    Was: $549.95
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    Was: $549.95
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  • On Sale
    New - H&K HK 416 14.5 Upper Receiver Assembly - OTB - Unfired - HKP-02095 HK416 Upper Receiver Assembly - 14.5" Barrel - OTB - Unfired
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    HK416 Upper Receiver Assembly - 14.5" Barrel - OTB - Unfired

    H&K Heckler & Koch

    Now: $9,999.95
    Was: $14,499.95
    Unfired "BF" Date Coded HK Factory German 416 14.5" Upper Kit No FFL is required. This upper assembly is only considered a part. This is a rare offering. All NFA rules apply - Check your local short barrel rifle regulations. Includes: HK 416...
    HKP-02095
    Now: $9,999.95
    Was: $14,499.95
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  • Out Of Stock
    New - H&K MR556 & HK416 (5.56x45/.223) Upper Conversion Kit - Threaded 1/2x28 - HKP-17877 HK416, MR556 Upper Conversion Kit - Threaded 1/2x28, - 5.56x45 / .223

    HK416, MR556 Upper Conversion Kit - Threaded 1/2x28, - 5.56x45 / .223

    HKP HK Parts

    $699.95
    H&K MR556 & HK416 (5.56x45/.223) Upper Conversion Kit - Threaded 1/2x28 Finally an answer for all of those that have been wanting a 14.5" upper for an HK416 or MR556. This conversion kit adds an upper or a barrel option for your MR556, CR556...
    HKP-17877
    $699.95
    Out Of Stock
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    $699.95
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  • Out Of Stock
    New - HKP HK MR556/416 Upper 9" 416C Style Conversion Kit - HKP-18674 HK416, MR556 Upper 9" 416C Style Conversion Kit

    HK416, MR556 Upper 9" 416C Style Conversion Kit

    HKP HK Parts

    $899.95
    MR556 & HK416 Upper Conversion Kit - 9" - HK 416C Style Finally an answer for all of those that have been wanting as close to the original, rare unicorn of a find HK 416C 9" barrel conversion kit for 416 or MR556. Each conversion kit upper or barrel...
    HKP-18674
    $899.95
    Out Of Stock
    Qty in Cart: 0
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    $899.95
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  • Out Of Stock
    New - HKP HK USC (.45 ACP) Carbine Mag Release - Extended - HKP-17918

    HK USC Magazine Release - Extended - .45 ACP

    HKP HK Parts

    $24.95
    HK USC Alloy Mag Release - Extended Billeted alloy USC magazine release. This is a very common repair & replacement part as they are fairly easy to break on the USC lower. With this new metal mag release you get more surface area as well as a much...
    HKP-17918
    $24.95
    Out Of Stock
    Qty in Cart: 0
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    $24.95
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  • Out Of Stock
    Used - H&K UMP (.40 S&W/.45 ACP/9mm) Demilled Rear Receiver Section - HKP-01659 HK UMP (.40 S&W/.45 ACP/9mm) Demilled Rear Receiver Section

    HK UMP (.40 S&W/.45 ACP/9mm) Demilled Rear Receiver Section

    H&K Heckler & Koch

    $0.00
    HK UMP Demilled Receiver Section This is a demilled factory HK UMP rear receiver section that is perfect for the new Tom Bostic USC-UMP conversions. This section is the perfect length in order to do the USC/UMP conversion. Last one available.
    HKP-01659
    $0.00
    Out Of Stock
    Qty in Cart: 0
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    $0.00
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  • Out Of Stock
    New - HK UMP (.40 S&W/.45 ACP/9mm) Paddle Mag Release - HKP-18773

    HK UMP Paddle Magazine Release

    $9.95
    UMP Paddle Magazine Release - US Made New UMP Mag release. This is a very common repair & replacement part as they are fairly easy to break on the UMP lower. Simple & easy to install no gunsmith needed or required. Compatible With: UMP .45 UMP ...
    HKP-18773
    $9.95
    Out Of Stock
    Qty in Cart: 0
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    $9.95
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