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/SL8 Complete Recoil Rod Assembly - HKP-01057
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    HK G36, SL8 Complete Recoil Rod Assembly

    H&K Heckler & Koch

    $69.95
    Recoil Rod Assembly for HK G36 & SL8 New HK factory German G36/SL8 (fits all variants of SL8/G36) recoil rod assembly complete. Great for replacement or for a spare as these have been hard to find.
    HKP-01057
    $69.95
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  • Out Of Stock
    Used - H&K MP5, MP5K Case Deflector - HKP-00871 HK MP5, MP5K Case Deflector

    HK MP5, MP5K Case Deflector

    H&K Heckler & Koch

    $0.00
    HK German case deflector for receiver flat or receiver for all MP5, HK94, MP5K & SP89 builds. The case deflector is riveted or welded in place on the ejection port of the 9mm receiver/flat to aid in the extraction of the 9mm round. HK MP5, 94 HK...
    HKP-00871
    $0.00
    Out Of Stock
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    $0.00
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  • Out Of Stock
    New - H&K HK G28 Buffer Tube - Black - HKP-16741 HK G28 Buffer Tube

    HK G28 Buffer Tube

    H&K Heckler & Koch

    $199.95
    HK G28 Buffer Tube / Receiver Extension New HK German buffer tube with the proper slot cut for use with the G28 stock. This is the factory correct part needed to get the full range and use of the G28 adjustable stock. Made in Germany by HK.
    HKP-16741
    $199.95
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    $199.95
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  • Out Of Stock
    New - HKP 416 10.4" 5.56 Complete Upper Receiver Assembly - HKP-17662 HK416 Upper Receiver Kit - 10.4" - 5.56

    HK416 Upper Receiver Kit - 10.4" - 5.56

    HKP HK Parts

    $2,485.95
    HKP 416 10.4" 5.56 Complete Upper Kit Complete Each kit includes the complete upper assembly, bolt group, tungsten buffer, & high-reliability SS recoil spring. This upper kit is a complete gas piston HK 416 style upper assembly that will drop on your...
    HKP-17662
    $2,485.95
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  • New - H&K HK MR556/416 Roll Pin for Charging Handle - HKP-17063
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    HK 416, MR556 Charging Handle Roll Pin

    H&K Heckler & Koch

    $7.95
    HK Clamping Sleeve or Roll Pin for Pawl On Charging Handle This is the longer one that is used on the outside of the charging handle. There are one of these pins used per charging handle.
    HKP-17063
    $7.95
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    $7.95
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  • New - HKP HK MP5 Receiver Flat - Smooth Top - HKP-21552 HK MP5 Receiver Flat - Smooth Top
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    HK MP5 Receiver Flat - Smooth Top

    HKP HK Parts

    $125.95
    HKP HK MP5 Receiver Flat - Smooth Top The MP5 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,...
    HKP-21552
    $125.95
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  • New - H&K HK MR556/MR223 Upper Receiver w/ F/A & Ejection Door - HKP-16950 HK MR556, MR223 Upper Receiver w/ F/A & Ejection Door
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    HK MR556, MR223 Upper Receiver w/ F/A & Ejection Door

    H&K Heckler & Koch

    $694.95
    New HK German Partially Pre-Assembled MR556/MR223 Upper Receiver Each unit comes just as shown with the F/A (forward assist) assembly and ejection port door assembly installed from the HK factory.  Compatible With: HK MR556 HK MR223 HK...
    HKP-16950
    $694.95
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  • New - H&K MR556 A4/416 Rear Takedown Pin - HKP-22029 HK416, HK417, MR556, MR762 Takedown Pin - Rear - A4 Style
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    HK416, HK417, MR556, MR762 Takedown Pin - Rear - A4 Style

    H&K Heckler & Koch

    $43.95
    H&K MR556, HK416, HK417, MR762 Rear Takedown Pin Factory A4 rear takedown pin.  Will work for A1 and A4 applications.   Compatible With: HK MR556 A1 and A4 HK416 HK MR762 A1 and A4 HK417 AR-14, M4, M16    
    HKP-22029
    $43.95
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  • Used - H&K HK MP5 Rear Receiver Section - HKP-02147
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    HK MP5 Lower Receiver - Section

    H&K Heckler & Koch

    $54.95
    HK MP5 Rear Receiver Section  HK German demilled receiver section with rear sight base as installed at the factory. The rear push pin section is still attached to the demilled receiver section.
    HKP-02147
    $54.95
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  • New - HKP MP5, MP5K Rear Sight Base - HKP-02450 HK MP5, MP5K Rear Sight Base
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    HK MP5, MP5K Rear Sight Base

    HKP HK Parts

    $19.95
    MP5 & MP5K Rear Sight Base- Weldment The only factory-correct sight base with the factory HK German side axis grooves.  Compatible With: HK MP5, 94 HK MP5K, SP89 HK MP5 40, MP5 10 MAC-5 clones may require custom fitment. Modified components are...
    HKP-02450
    $19.95
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  • New - H&K HK G36 Backplate Complete w/ Recoil Assembly - HKP-16735 HK G36 Backplate Complete with Recoil Assembly
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    HK G36 Backplate Complete with Recoil Assembly

    H&K Heckler & Koch

    $199.95
    HK G36 Backplate Complete With Recoil Assembly New HK German G36 Backplate with new G36/SL8 recoil buffer and recoil assembly. This assembly does include the recoil rod retaining screw. This is a great spare or replacement to have on hand. These are also...
    HKP-16735
    $199.95
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  • New - H&K HK MR762/417 Flush Cup QD End Plate - Black - HKP-21642 HK417, MR762 QD End Plate - Flush Cup
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    HK417, MR762 QD End Plate - Flush Cup

    H&K Heckler & Koch

    $152.95
    H&K HK MR762/417 Flush Cup QD End Plate Factory HK flush end cap with dual QD sockets for ambidextrious sling attachment. Compatible With: HK MR762 HK 417
    HKP-21642
    $152.95
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    $152.95
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