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

    HK417, MR762 Ejection Port Cover

    H&K Heckler & Koch

    $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
    HKP-16598-M
    $42.95
    Qty in Cart: 0
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    $42.95
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  • Out Of Stock
    New - H&K USC (.45 ACP) Carbine Mag Release Axle - HKP-02584

    HK USC Magazine Release Axle

    H&K Heckler & Koch

    $18.95
    Heckler and Koch .45 ACP Magazine Release Axle for HK USC Replacement magazine release axle for HK USC .45 ACP platforms. This component is commonly replaced due to wear or breakage and may also be...
    HKP-02584
    $18.95
    Qty in Cart: 0
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    $18.95
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  • On Sale
    New - HKP AR-15 Commercial Buffer Tube Kit - HKP-02736 HKP AR-15 Commercial Buffer Tube Kit HKP HK Parts HKP-02736

    AR-15 Commercial Buffer Tube Kit

    HKP HK Parts

    Now: $20.96
    Was: $47.95
    AR-15 Commercial Buffer Tube Kit Compatible With: All AR-15 style platforms  Not correct length for HK rifles Includes
    HKP-02736
    Now: $20.96
    Was: $47.95
    Qty in Cart: 0
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    Now: $20.96
    Was: $47.95
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  • New - H&K HK MR762/417 Charging Handle Pin - HKP-16754

    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: <
    HKP-16754
    $6.95
    Qty in Cart: 0
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    $6.95
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  • Out Of Stock
    New - HK33, HK53, HK93 (5.56/.223) Magazine Catch - Latest Design - HKP-01059

    HK33, HK53, HK93 Magazine Catch - Latest Design

    H&K Heckler & Koch

    $49.95
    Heckler and Koch German Factory Magazine Catch for HK33, HK53, HK93 New HK German HK33, HK53, and HK93 mag catch for magazine release. 
    HKP-01059
    $49.95
    Qty in Cart: 0
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    $49.95
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  • New - H&K HK MR762/417 Cylindrical Pin For Stop Pin - HKP-16619

    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
    Qty in Cart: 0
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    $9.95
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  • New - HKP MP5K 40/10 Receiver Flat - HKP-18033 HK MP5K Receiver Flat - .40 S&W, 10mm

    HK MP5K Receiver Flat - .40 S&W, 10mm

    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
    HKP-18033
    $199.95
    Qty in Cart: 0
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    $199.95
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  • Out Of Stock
    New - H&K HK MR556/416 Enhanced Buffer Tube - Tan - HKP-22086 HK416, MR556 Enhanced Buffer Tube - Tan

    HK416, MR556 Enhanced Buffer Tube - Tan

    H&K Heckler & Koch

    $192.95
    Tan HK 416, MR556 OTB (over the beach) Buffer Tube, Receiver Extension - Commercial Genuine HK German-manufactured 416 & MR556 latest generation, marine environment & and over-the-beach buffer tube...
    HKP-22086
    $192.95
    Qty in Cart: 0
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    $192.95
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  • New - H&K 416A5 RAL 8K Stripped Upper Receiver - HKP-18787 HK416 A5 Stripped Upper Receiver - RAL8000

    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
    HKP-18787
    $1,559.95
    Qty in Cart: 0
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    $1,559.95
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  • New - HKP HK G36/SL8 (5.56/.223) Cocking Handle - HKP-18251 HK G36, SL8 Cocking Handle

    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
    Qty in Cart: 0
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    $49.95
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  • Out Of Stock
    New - MM HK 21 (7.62x51/.308) Factory Style T- Rail Set - HKP-00823 HK21 T-Rail Set - Factory Style

    HK21 T-Rail Set - Factory Style

    Michaels Machines

    $275.00
    Michael's Machines HK 21 (7.62x51/.308) Factory Style T-Rail Set HK21 US-made rails for all HK21 builds. This is similar to the rails above, only prepped/cut for the HK21 feed mechanism.  
    HKP-00823
    $275.00
    Qty in Cart: 0
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    $275.00
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