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 MR556/416 E1 Charging Handle - Ambidextrous - HKP-01959

    HK416 E1, MR556 Charging Handle - Ambidextrous

    H&K Heckler & Koch

    $129.95
    H&K HK MR556/416 E1 Charging Handle - Ambidextrous HK's design boasts a smooth & easy to release latch with an enhanced oversized charging handle.  Compatible With: HK MR556 HK 416 Other AR15, M4 & M16 applications
    HKP-01959
    $129.95
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  • New - RCM HK G3, HK 91, PTR Trunnion - HKP-01289 HK91, G3, PTR Trunnion
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    HK91, G3, PTR Trunnion

    RCM

    $64.95
    RCM Trunnion For The HK91/G3 Series - US Made This part is machined from ordnance grade 9310 enhanced steel and heat treated to exact HK specifications. This item is the best USA-made trunnion on the market. Machined to spec and are to the custom ground...
    HKP-01289
    $64.95
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  • New - H&K MP5, HK94 Case Deflector Rivet - HKP-00147 HK MP5, HK94 Case Deflector Rivet
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    HK MP5, HK94 Case Deflector Rivet

    H&K Heckler & Koch

    $9.95
    H&K MP5, HK94 Case Deflector Rivet Each case deflector, US or German-made, will require two rivets to attach the case deflector to the receiver or flat. If you want the factory look and feel of doing it right, these rivets are a must-have. These are...
    HKP-00147
    $9.95
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  • New - H&K HK MR556 Receiver Take Down Tool - HKP-02653
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    HK MR556 Receiver Take Down Tool

    H&K Heckler & Koch

    $19.95
    H&K HK MR556 Receiver Take Down Tool This part is the tool used to tighten down the stock movement on the E1/E2 stock. Each tool will be stored in the rear of the E1/E2 stock. Compatible With: HK MR556 Please Note: We get...
    HKP-02653
    $19.95
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  • New - H&K MP5 & MP5K 9mm Anti-Rattle Roller Tipped "Paddle" Magazine Release - HKP-00117 HK MP5, MP5K Magazine Release Paddle - Anti-Rattle Roller-Tip - 9mm
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    HK MP5, MP5K Magazine Release Paddle - Anti-Rattle Roller-Tip - 9mm

    H&K Heckler & Koch

    $64.95
    Heckler and Koch Anti-Rattle Roller Tipped "Paddle" Magazine Release for HK MP5, MP5K Factory German made Paddle mag release for all 9mm MP5, MP5K HK builds. Our parts are made by HK in Germany and are factory-fresh production. Compatible With: MP5,...
    HKP-00117
    $64.95
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  • Out Of Stock
    New - H&K HK MR556/416 Castle Nut - HKP-15230 HK416, MR556 Buffer Tube Castle Nut

    HK416, MR556 Buffer Tube Castle Nut

    H&K Heckler & Koch

    $34.95
    Heckler and Koch Castle Nut for Buffer Tube for HK416 and HK MR556 New HK German manufacture. This buffer tube castle nut will fit both mil-spec and commercial buffer tubes. All steel manufacture. With HK round tool attachment points as well as...
    HKP-15230
    $34.95
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  • New - HK G36/SL8 (5.56/.223) Factory Recoil Buffer - HKP-18541
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    HK G36, SL8 Recoil Buffer - Factory - US

    USA

    $16.95
    HK G36 Or SL8 Factory Recoil Buffer A must have spare part as the buffer is prone to wear and breakage. Compatible With: All HK G36 models SL8 models Clones
    HKP-18541
    $16.95
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  • HK416, MR556 Buffer Tube Wrench HK416, MR556 Buffer Tube Wrench
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    HK416, MR556 Buffer Tube Wrench

    HKP HK Parts

    $29.95
    HK MR556 & HK416 Buffer Tube Wrench The perfect metric wrench to remove and install the MR556 & HK 416 castle nuts on the buffer tube. A perfect addition to have on hand for OTB or other HK buffer tube upgrades, etc. Made from all steel, heat...
    HKP-17124
    $29.95
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  • Out Of Stock
    New - H&K HK MR556/416 Receiver End Plate - HKP-16603 HK416, MR556 Receiver End Plate

    HK416, MR556 Receiver End Plate

    H&K Heckler & Koch

    $24.95
    HK 416, MR556 End Plate For Receiver & Buffer Tube New HK German manufacture. Compatible With: HK MR556 & HK 416 upper receiver/buffer tubes
    HKP-16603
    $24.95
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  • On Sale
    New - HKP MP5 40/10 Receiver Flat - HKP-00767 HK MP5 Receiver Flat - .40 S&W, 10mm
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    HK MP5 Receiver Flat - .40 S&W, 10mm

    HKP HK Parts

    Now: $194.95
    Was: $399.95
    MP5 40 & MP5 10mm Receiver Flat - USA The new and latest production with the weldment locations is already lasered and ready to go. This flat is the finest available for the MP5 40/10 family of firearms. Compatible With: MP5 .40 Cal MP5 10mm MP5 ...
    HKP-00767
    Now: $194.95
    Was: $399.95
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    Now: $194.95
    Was: $399.95
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  • New - H&K MP5 Magazine Release Set - HKP-02402 HK MP5, MP5K Magazine Release Set
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    HK MP5, MP5K Magazine Release Set

    H&K Heckler & Koch

    $184.95
    Heckler and Koch Magazine Release Set for HK MP5 and HK MP5K This is the complete magazine release kit that includes both the paddle mag release and standard left-to-right mag release on your HK 9mm rifle or pistol build.  Set...
    HKP-02402
    $184.95
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  • MKE HK MP5/MP5K Magazine Release Bushing MKE HKP-22283 MKE HK MP5/MP5K Magazine Release Bushing MKE HKP-22283
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    HK MP5, HK90 Series Paddle Mag Release Bushing - Full Auto

    MKE

    $2.59
    MKE Magazine Release Bushing for HK MP5, MP5K and HK90 Firearms This part is for use in all HK90-series Heckler and Koch weapon systems and is used for installing a paddle mag release. This is not for use on semi-auto HK builds. This part is intended for...
    HKP-22283
    $2.59
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