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 - H&K HK G36, HK SL8 Roll Pin for Gas Piston - Black - HKP-16386

    HK G36, SL8 Roll Pin - Gas Piston

    H&K Heckler & Koch

    $9.95
    H&K HK G36, HK SL8 Roll Pin for Gas Piston
    HKP-16386
    $9.95
    Out Of Stock
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  • New - H&K HK MR762/417 Charging Handle Pin - HKP-16754
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    HK417, MR762 Charging Handle Pin

    H&K Heckler & Koch

    $6.95
    H&K HK MR762/417 Charging Handle Pin HK MR762 & HK 417 Clamping Sleeve for plate on charging handle. There are two of these pins used on the charging handle. Compatible With: HK MR762 HK 417
    HKP-16754
    $6.95
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  • New - HKP HK G36/SL8 (5.56/.223) Cocking Handle - HKP-18251 HK G36, SL8  Cocking Handle
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    HK G36, SL8 Cocking Handle

    HKP HK Parts

    $49.95
    Cocking Handle For G36 & SL8 Bolt Carriers - USA New USA made charging handle ideal for a 922 replacement part. Made in the USA.
    HKP-18251
    $49.95
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  • New - HKP MP5K 40/10 Receiver Flat - HKP-18033 HK MP5K Receiver Flat - 10mm / .40 S&W -
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    HK MP5K Receiver Flat - 10mm / .40 S&W -

    HKP HK Parts

    $199.95
    MP5K-40, MP5K-10 Receiver Flat - USA Receiver Flat for use with a MP5K-40 or MP5K-10mm build. Please note: This is for the flat as picture no weldments are included. ***This US made receiver flat counts as one required 922r compliant part***
    HKP-18033
    $199.95
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  • New - H&K HK MR762/417 Cylindrical Pin For Stop Pin - HKP-16619
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    HK417, MR762 Cylindrical Pin for Stop Pin

    H&K Heckler & Koch

    $9.95
    H&K HK MR762/417 Cylindrical Pin For Stop Pin HK 2x18 mm pin designed for use with the rear take down pin detent and spring. Compatible With: HK MR762 HK 417
    HKP-16619
    $9.95
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  • On Sale
    New - HK MP5 Trunnion - Gunsmith Special - HKP-99089 HK MP5 Trunnion - Gunsmith Special
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    HK MP5 Trunnion - Gunsmith Special

    USA

    Now: $24.95
    Was: $54.95
    HK MP5 Trunnion - Gunsmith Special US made HK MP5 trunnions sold as-is. Will require work before being functional. We recommend the work be performed by a professional gunsmith. The condition will vary from part-to-part vs. the pictured unit. Compatible...
    HKP-99089
    Now: $24.95
    Was: $54.95
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  • Out Of Stock
    New - H&K HK MR762/417 Charging Handle Catch - HKP-16852 HK417, MR762 Charging Handle Catch

    HK417, MR762 Charging Handle Catch

    H&K Heckler & Koch

    $59.95
    HK MR762, HK417 Extended Charging Handle Catch Complete  New HK German manufacture. A great part to have on hand as these are prone to breakage and wear. Compatible With: HK MR762 HK 417 HK G28
    HKP-16852
    $59.95
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  • New - H&K G36 (5.56/.223) Cocking Handle Bushing - HKP-01869
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    HK G36 Cocking Handle Bushing

    H&K Heckler & Koch

    $9.95
    HK German G36 Cocking Handle Bushing
    HKP-01869
    $9.95
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  • New - H&K 416A5 RAL 8K Stripped Upper Receiver - HKP-18787 HK416 A5 Stripped Upper Receiver - RAL8000
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    HK416 A5 Stripped Upper Receiver - RAL8000

    H&K Heckler & Koch

    $1,559.95
    HK German Un-Assembled - Stripped HK416 A5 Upper Receiver - RAL 8K Brand new factory German RAL 8000 HK416A5 upper receiver. Compatible With: HK416 HK MR556 HK MR223 Looking for a matching lower for your build?  STS416 A5 LOWER - Specialized...
    HKP-18787
    $1,559.95
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  • New - HKP AR-15 Commercial Buffer Tube Kit - HKP-02736 HKP AR-15 Commercial Buffer Tube Kit HKP HK Parts HKP-02736
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    HK416, MR556, AR-15 Commercial Buffer Tube Kit

    HKP HK Parts

    $47.95
    AR-15 Commercial Buffer Tube Kit Compatible With: HK MR556 & 416  All AR-15 style platforms  Includes: Made with T7 7075 aircraft-grade aluminum Made in the USA with a polished inside tube Mil-Spec triple hard coat Teflon anodized...
    HKP-02736
    $47.95
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  • HK21E Feed Mechanism - Complete - 7.62 / .308
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    HK21E Feed Mechanism - Complete - 7.62 / .308

    H&K Heckler & Koch

    $22,495.95
    HK21E Feed Mechanism Complete - German HK - DM1 Links New genuine HK date-coded and marked 21E complete feed mechanism. These are the last of the genuine feed mechs available and due to the HK officially discontinuing the 21E, no additional factory units...
    HKP-00584
    $22,495.95
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  • On Sale
    New - H&K HK416A1 10.4" Upper Receiver Kit - AI Date Code (2008) - PD Trade-In - HKP-22245 H&K HK 416 10.4 - AI Upper H&K Heckler & Koch HKP-22245
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    HK416 A1 Upper Receiver - 10.4"

    H&K Heckler & Koch

    Now: $2,999.95
    Was: $3,499.95
    HK416 10.4" Complete Upper Receiver Features: Factory German 10.4" length 2008 date coded   P.D. trade-in, de-serialized during the de-milling process.  Finish your build with a matching lower from STS Tactical. Compatible With: HK416
    HKP-22245
    Now: $2,999.95
    Was: $3,499.95
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