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
    HK417, MR762 Ejection Port Cover New - H&K HK MR762/417 Ejection Port Cover - HKP-16598
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    HK417, MR762 Ejection Port Cover

    H&K Heckler & Koch

    Now: $38.66
    Was: $42.95
    H&K HK MR762/417 Ejection Port Cover New HK German polymer .308 style MR762, HK 417 & G28 firearms. Compatible With: HK MR762 HK 417 HK G28 Other HK Spec .308 firearms
    Now: $38.66
    Was: $42.95
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    Was: $42.95
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  • On Sale
    New - H&K MR556/416 E2 Charging Handle - HKP-22021 HK416, MR556 Charging Handle - E2
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    HK416, MR556 Charging Handle - E2

    H&K Heckler & Koch

    Now: $125.95
    Was: $139.95
    Heckler and Koch E2 Charging Handle for HK416, MR556 Factory HK charging handles for the MR556, HK416 platform. The standard MR556 charging handle allows the release latch to be configured on either the right or left side for user preference. The HK E2...
    Now: $125.95
    Was: $139.95
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  • On Sale
    New - H&K HK MR762/417 Charging Handle Catch - HKP-16852 HK417, MR762 Catch - Charging Handle
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    HK417, MR762 Catch - Charging Handle

    H&K Heckler & Koch

    Now: $53.96
    Was: $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
    Now: $53.96
    Was: $59.95
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  • On Sale
    New - H&K HK MR762/417 Charging Handle Pin - HKP-16754
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    HK417, MR762 Pin - Charging Handle

    H&K Heckler & Koch

    Now: $6.25
    Was: $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
    Now: $6.25
    Was: $6.95
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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: $2,699.95
    Was: $3,499.95
    Heckler and Koch's 10.4" Complete Upper Receiver Kit for your HK416 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...
    Now: $2,699.95
    Was: $3,499.95
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  • On Sale
    Used - H&K 416 10.4" Date Coded OTB Upper Receiver Kit - USED - HKP-22193-M HK416 Upper Receiver Kit - 10.4" - Date Coded - OTB - USED
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    HK416 Upper Receiver Kit - 10.4" - Date Coded - OTB - USED

    H&K Heckler & Koch

    Now: $3,410.95
    Was: $3,789.95
    H&K 416 10.4" Date Coded OTB Upper Parts Kit - USED Genuine HK 416 10.4″ date coded used upper parts kit with a factory German 10.4″ barrel with the new Over The Beach (OTB) features (vented gas block, quad rail forearm).  Finish...
    Now: $3,410.95
    Was: $3,789.95
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    Now: $3,410.95
    Was: $3,789.95
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  • On Sale
    Used - HK G3 - FMP Early Type Demilled Front End - HKP-20845 HK G3 - FMP Early Type Demilled Front End
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    HK G3 - FMP Early Type Demilled Front End

    FMP HK CONTRACT

    Now: $89.95
    Was: $99.95
    HK G3 - FMP Early Type Demilled Front End Early style G3 front end with no hanger. These are the perfect option for those doing custom builds. Good condition over all. Includes: Cocking tube Complete cocking handle assembly Trunnion Barrel pin
    Now: $89.95
    Was: $99.95
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    Was: $99.95
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  • On Sale
    New - H&K HK MR762/417 Enhanced Buffer Tube - Black - HKP-16770 HK417, MR762 Enhanced Buffer Tube
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    HK417, MR762 Enhanced Buffer Tube

    H&K Heckler & Koch

    Now: $121.45
    Was: $134.95
    H&K HK MR762/417 Enhanced Buffer Tube/Receiver Extension - Black Brand new factory HK German manufactured MR762, MR308, & HK 417 buffer tube. Compatible With: HK MR762 HK 417
    Now: $121.45
    Was: $134.95
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    Was: $134.95
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  • Out Of Stock
    On Sale
    New - MM HK PSG1/MSG90/91/G3 (7.62x51/.308) T-Rail Reinforcement Set For Receiver - HKP-00236

    HK91, G3, PSG1, MSG90 T-Rail Reinforcement Set for Receiver

    Michaels Machines

    Now: $269.95
    Was: $299.95
    HK Receiver Reinforcement T-Rail Set For Left and Right Sides T-rails are used to strengthen HK receivers or for custom builds. These are the finest T-rails available on the market. Made from enhanced steel and perfect for that custom HK project...
    Now: $269.95
    Was: $299.95
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    Now: $269.95
    Was: $299.95
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  • Out Of Stock
    On Sale
    New - HKP MP5, 94 Trunnion 9mm - USA - HKP-17934 HK MP5, HK94 Trunnion - 9mm - USA

    HK MP5, HK94 Trunnion - 9mm - USA

    HKP HK Parts

    Now: $43.96
    Was: $54.95
    HKP MP5, 94 Trunnion 9mm - USA US made to exact factory HK specifications for the HK MP5, 94 type builds. Machined completely from ordnance grade steel and heat treated to factory specs. These are the best USA made trunnions on the market. Machined to HK...
    Now: $43.96
    Was: $54.95
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  • Out Of Stock
    On Sale
    New - HKP HK MP5K Receiver Flat - Smooth Top - HKP-21550 HK MP5K Receiver Flat - Smooth Top

    HK MP5K Receiver Flat - Smooth Top

    HKP HK Parts

    Now: $103.96
    Was: $129.95
    HKP HK MP5K Receiver Flat - Smooth Top The MP5K receiver flat has been meticulously crafted by the original German tool and die maker of the LSC receiver flat, utilizing factory original German prints and specifications. This receiver boasts a flat top,...
    Now: $103.96
    Was: $129.95
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    Was: $129.95
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  • On Sale
    New - H&K HK MR556/MR223 A5 Incomplete Upper Receiver - Black - HKP-18785 HK MR556, MR223 A5 Incomplete Upper Receiver
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    HK MR556, MR223 A5 Incomplete Upper Receiver

    H&K Heckler & Koch

    Now: $440.95
    Was: $489.95
    HK German Un-Assembled/Stripped HK MR556/MR223 A5 Upper Receiver Factory HK MR556 A5 upper receiver. This is the semi-auto MR556 variant. Compatible With: HK MR556 HK MR223 HK 416*** Need a matching lower for your build?  STS416 A5 LOWER -...
    Now: $440.95
    Was: $489.95
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    Now: $440.95
    Was: $489.95
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