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 - MI HK MP5K 1913 End Plate Adapter - HKP-21584 HK MP5K Picatinny End Plate Adapter
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    HK MP5K Picatinny End Plate Adapter

    MI Midwest Industries

    $89.95
    MI HK MP5K 1913 Picatinny End Plate Adapter The Midwest Industries Picatinny end plate adapter opens up a myriad of off-the-shelf stock and brace options. The adapter installs in the same manner as the factory end cap with the factory push pins...
    HKP-21584
    $89.95
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  • Out Of Stock
    New - RCM HK G3, HK 91, PTR Trunnion - HKP-01289 HK91, G3, PTR Trunnion

    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 VP9B Mag Release Button Set - S, L, XL - HKP-19746 HK VP9B Mag Release Button Set - S, L, XL
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    HK VP9B Mag Release Button Set - S, L, XL

    H&K Heckler & Koch

    $9.95
    HK VP9B Mag Release Button  - S, L & XL New HK German Manufacture. Will fit the new VP9B button mag release model. A perfect way to customize your mag release fitment. Compatible With: VP9B and VP9LB models only NOT compatible with VP9A1 F,...
    HKP-19746
    $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 UMP (.40 S&W/.45 ACP/9mm) Paddle Mag Release - HKP-00810
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    HK UMP Paddle Magazine Release

    H&K Heckler & Koch

    $16.95
    UMP Paddle Magazine Release This is a common repair and replacement part as they are easy to break on the UMP lower. Simple and easy to install with no gunsmith needed or required. Compatible With:  UMP .45 UMP .40 UMP 9mm Please Note: This...
    HKP-00810
    $16.95
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  • Out Of Stock
    New - HK Rifle Tac Latch - HK 91, G3, HK 93, 33 - HKP-02791 HK91, G3, HK33, HK53 HK93 Tac Latch

    HK91, G3, HK33, HK53 HK93 Tac Latch

    $69.95
    HK Rifle Tac Latch For HK 91, G3, HK 93, & 33 HK's were designed to have a quick one-handed release capability for the magazine (paddle mag release). However, the semi-auto versions eliminated this much-needed feature due to import restrictions...
    HKP-02791
    $69.95
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  • New - H&K HK MR556/416 Receiver End Plate - HKP-16603 HK416, MR556 Receiver End Plate
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    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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  • 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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  • 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
    German HK MP5, MP5K Anti-Rattle Roller Tipped "Paddle" Magazine Release Factory German 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, 94, HK SP5 MP5K, SP89,...
    HKP-00117
    $64.95
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  • HK91, G3, HK33, HK93 Bayonet Adapter - Complete - Turkish Contract HK91, G3, HK33, HK93 Bayonet Adapter - Complete - Turkish Contract
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    HK91, G3, HK33, HK93 Bayonet Adapter - Complete - Turkish Contract

    Other

    $38.95
    Turkish Contract Complete Bayonet Adapter for HK91, HK G3, HK33, HK93 Complete Turkish contract 90 Series-style steel bayonet adapter supplied with the required mounting hardware. Designed for proper fit on HK33, HK93, HK91, and G3 pattern rifles...
    HKP-22517
    $38.95
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