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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    New - HKP AR-15 Commercial Buffer Tube - HKP-02728
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    AR-15 Commercial Buffer Tube

    HKP HK Parts

    Now: $16.95
    Was: $24.95
    AR-15 Commercial Buffer Tube Compatible With: All AR-15 style platforms Not correct length for HK rifles Features: Made From T7 7075 Aircraft grade aluminum Made in the USA 6 Position Each features a highly polished inside tube Black...
    HKP-02728
    Now: $16.95
    Was: $24.95
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  • New - HKP MP5 40/10 Trunnion - HKP-02737 HK MP5 Trunnion - .40 S&W, 10mm
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    HK MP5 Trunnion - .40 S&W, 10mm

    HKP HK Parts

    $139.95
    MP5 40 & MP5 10mm Trunnion Machined from ordnance-grade steel and heat-treated to factory specs. Each has the bullet guides pre-installed and included. These are the best USA-made trunnions on the market. Machined to HK spec, making the installation...
    HKP-02737
    $139.95
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  • New - HKP HK MP5K/SP89 9mm Flat Receiver - HKP-20733 HK MP5K, SP89 Flat Receiver - 9mm
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    HK MP5K, SP89 Flat Receiver - 9mm

    HKP HK Parts

    $199.95
    MP5K, SP89 Receiver Flat - 9mm New MP5K receiver flat made by the original German tool and die maker of the LSC receiver flat utilizing factory original German prints and specifications. The creator of our receiver flat has been regarded as the premier...
    HKP-20733
    $199.95
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  • New - H&K MR762 A4 Pivot Pin - HKP-21958 HK417, MR762 Takedown Pin - Front - A4 Style
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    HK417, MR762 Takedown Pin - Front - A4 Style

    H&K Heckler & Koch

    $43.99
    H&K MR762 A4 Receiver Front Takedown Pin German-made factory pivot pin for the MR762 A4.  Will work with A1 models as well. Compatible With: HK MR762 A1 and A4 HK417  
    HKP-21958
    $43.99
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  • New - HKP Front Sight Tower Ambi Sling Attachment Weldment - HKP-17881 HK MP5, MP5K Sling Attachment Weldment - Ambi - Front End
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    HK MP5, MP5K Sling Attachment Weldment - Ambi - Front End

    HKP HK Parts

    $14.95
    HKP Front Sight Tower Ambi Sling Attachment Weldment Ambi sling loop that is welled and installed on all MP5F model front sight tower. A great upgrade for that custom build or for those that want to have the ability to have an ambidextrous sling loop at...
    HKP-17881
    $14.95
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  • New - HK 416, MR556 Roll Pin for Charging Handle - HKP - HKP-16536
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    HK416, MR556 Charging Handle Roll Pin

    $7.95
    HK 416, MR556 Roll Pin for Charging Handle - HKP This is the shorter one that is used on the inside of the charging handle. There are two of these pins used per charging handle.
    HKP-16536
    $7.95
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  • New - HK G36/SL8 (5.56/.223) Cocking Handle Spring - HKP-18369 HK G36, SL8 Cocking Handle Spring - US
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    HK G36, SL8 Cocking Handle Spring - US

    $9.95
    G36 Cocking Handle Spring- US Made   Compatible With: G36 All variants SL8 All variants
    HKP-18369
    $9.95
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  • New - H&K G36/SL8 (5.56/.223) Cocking Handle Spring - HKP-01862
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    HK G36, SL8 Cocking Handle Spring

    H&K Heckler & Koch

    $10.95
    HK German G36 Cocking Handle Spring - All Variants Compatible With: G36 - all variants SL8 - all variants
    HKP-01862
    $10.95
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  • HK91, G3 Magazine Release Set, Complete - USED HK91, G3 Magazine Release Set, Complete - USED
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    HK91, G3 Magazine Release Set, Complete - USED

    H&K Heckler & Koch

    $24.95
    Heckler and Koch Magazine Release Set (Left to Right) for HK91 and G3 This HK German manufactured, used magazine release set for HK .308 pattern rifles consists of 6 pieces. Complete left-to-right mag catch assembly with both push-button and paddle...
    HKP-22466
    $24.95
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  • Out Of Stock
    New - HKP HK 416C 9" Complete Upper Receiver Assembly - HKP-21042 HK416C Upper Receiver Kit - 9"

    HK416C Upper Receiver Kit - 9"

    HKP HK Parts

    $2,799.95
    HK416C Complete Upper Kit - 9"  Our complete 416C upper kit includes everything you need to pair with a mil-spec lower or an STS 416C lower. For that genuine look, the STS 416C lower with the correct 416C stock eyelets is as good as you can get...
    HKP-21042
    $2,799.95
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  • New - H&K HK G36, HK SL8 Magazine Paddle Release - HKP-02152 HK G36, SL8 Paddle Magazine Release
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    HK G36, SL8 Paddle Magazine Release

    H&K Heckler & Koch

    $19.95
    Heckler and Koch Paddle Magazine Release for HK G36 and HK SL8 Compatible With: SL8 G36 G36K G36C
    HKP-02152
    $19.95
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  • Flat Bending Jig Set For All HK Style Flats - RENTAL HKP HK Parts HKP-19595-RENTAL HK Receiver Flat Bending Set Jig - RENTAL
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    HK Receiver Flat Bending Set Jig - RENTAL

    HKP HK Parts

    $99.95
    Flat Bending Jig Set For All HK Style Receiver Flats - RENTAL Receiver flat bending jig RENTAL for all HK receiver flats.  Our rental jigs are crafted in the US from billeted steel and include the latest revisions with proper dowel spacing for the...
    HKP-19595-RENTAL
    $99.95
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