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
    New - HKP HK MP5 .22 Sling Clip Kit - Black - HKP-15706 HK MP5 .22 Sling Clip Kit
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    HK MP5 .22 Sling Clip Kit

    HKP HK Parts

    Now: $19.95
    Was: $24.95
    HKP HK MP5 .22 Sling Clip Kit Each unit will fit all models of the MP5 .22 that have the 3 mounting holes on the left side of the magwell. This item installs in a few mins and comes complete with all you need for the install. With the addition of this...
    HKP-15706
    Now: $19.95
    Was: $24.95
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  • On Sale
    New - LSC MP5 9mm Receiver Flat - HKP-20555 HK MP5 Receiver Flat - 9mm - US Made
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    HK MP5 Receiver Flat - 9mm - US Made

    LSC

    Now: $169.95
    Was: $199.95
    MP5 Receiver Flat - LSC LSC HK MP5 receiver flat is the most in spec flat that has ever been available. The best option for your HK German parts kit build. This flat is considered by many to be most sought after HK flat available on the market and...
    HKP-20555
    Now: $169.95
    Was: $199.95
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    Was: $199.95
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  • On Sale
    New - HKP HK MP5/MP5K 4-Piece Set Magazine Release - HKP-00912 HK MP5, MP5K Magazine Release Set - 4 Piece
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    HK MP5, MP5K Magazine Release Set - 4 Piece

    HKP HK Parts

    Now: $63.95
    Was: $79.95
    HKP HK Parts 4-Piece Magazine Release Set for HK MP5 and HK MP5K Each magazine catch set consists of 4 pieces and is a mixture of HK Germany and USA made parts. This is the set that provides left-to-right mag release controls. Each Set Includes: Mag...
    HKP-00912
    Now: $63.95
    Was: $79.95
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    Was: $79.95
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  • Out Of Stock
    New - HKP HK 416/MR556 A5 Style Castle Nut-Extended - HKP-18058

    HK416, MR556 Buffer Tube Castle Nut - A5 Extended

    HKP HK Parts

    $39.95
    HKP HK Parts A5 Style Extended Length Castle Nut for HK 416, MR556 Unlike the factory German A5 castle, our A5 extended buffer tube castle nut is compatible with both mil-spec and commercial buffer tubes. Crafted from ordnance grade steel and nitrided...
    HKP-18058
    $39.95
    Out Of Stock
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    $39.95
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  • On Sale
    HK UMP, USC Top Receiver Rail - Enhanced - Picatinny HK UMP, USC Top Receiver Rail - Enhanced - Picatinny
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    HK UMP, USC Top Receiver Rail - Enhanced - Picatinny

    HKP HK Parts

    Now: $39.95
    Was: $49.95
    HKP HK Parts US Made Top Receiver Rail with Hardware for HK USC and UMP The extended length allows the use of all optics that fit on a Picatinny rail. This unit has a contoured, no-snag design for ease of use and a beautiful fit. Made from billet...
    HKP-14541-M
    Now: $39.95
    Was: $49.95
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    Was: $49.95
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  • On Sale
    Used - IMI UZI Lower, Grip Complete - HKP-16683 IMI UZI Lower, Grip Complete IMI HKP-16683
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    UZI Lower with Grip Complete

    IMI

    Now: $89.95
    Was: $99.95
    Uzi Lower Complete - IMI Manufactured For The German Military Surplus IMI Manufactured Uzi Grip (lower) complete with all internals as shown. Each lower comes complete with all internals, grips and mag release assembly installed. Perfect for spare parts...
    HKP-16683
    Now: $89.95
    Was: $99.95
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    Now: $89.95
    Was: $99.95
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  • On Sale
    New - HKP HK MR762/417/G28 Buffer Tube Wrench - Black - HKP-17111 HK417, MR762, G28 Buffer Tube Wrench
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    HK417, MR762, G28 Buffer Tube Wrench

    HKP HK Parts

    Now: $23.95
    Was: $29.95
    HKP HK MR762/417/G28 Buffer Tube Wrench The perfect metric wrench to remove and install the MR762 & G28 castle nuts on the buffer tube. A perfect addition to have on hand for G28 buffer tube upgrades, etc. Made from all steel, heat treated and made...
    HKP-17111
    Now: $23.95
    Was: $29.95
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    Now: $23.95
    Was: $29.95
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  • On Sale
    HK Receiver Flat Bending Jig Set - Billet Steel HK Receiver Flat Bending Jig Set - Billet Steel
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    HK Receiver Flat Bending Jig Set - Billet Steel

    HKP HK Parts

    Now: $479.95
    Was: $599.95
    Flat Bending Jig Set For All HK Style Flats - Billeted - All Steel All steel billeted universal flat bending jig for all HK receiver flats including PTR .308 flats and the PTR/LSC flats. Each bending jig comes complete with all the pieces you need for...
    HKP-19595
    Now: $479.95
    Was: $599.95
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    Now: $479.95
    Was: $599.95
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  • On Sale
    New - HKP MP5/HK94 Complete Weldment Set For Receiver Flat - HKP-01453
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    HK MP5, HK94 Complete Weldment Set For Receiver Flat

    HKP HK Parts

    Now: $50.95
    Was: $59.95
    HKP MP5/HK94 Complete Weldment Set For Receiver Flat This is the finest, most correct weldment set for your HK MP5, 94 project available.  Each Weldment Kit Contains: 1x Semi Auto Shelf Hanger Block 1x Rear stock bushing 1x Scope mounting piece 1x...
    HKP-01453
    Now: $50.95
    Was: $59.95
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  • Out Of Stock
    New - HKP MP5, MP5K 9mm Contact Piece for Paddle Mag Release - HKP-17403 HK MP5, MP5K Paddle Mag Release Contact Piece - USA

    HK MP5, MP5K Paddle Mag Release Contact Piece - USA

    HKP HK Parts

    $15.95
    HKP HK Parts 9mm Contact Piece HK MP5 and HK MP5K Factory correct US manufactured MP5, MP5K 9mm Contact Piece for Paddle magazine release. Each part was made using the same material and manufacturing methods used on the German HK latest production parts...
    HKP-17403
    $15.95
    Out Of Stock
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    $15.95
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  • On Sale
    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

    Now: $34.95
    Was: $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
    Now: $34.95
    Was: $38.95
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    Now: $34.95
    Was: $38.95
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  • New - H&K HK MR556/MR762/416 Buffer Retainer Pin - HKP-12704
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    HK416, MR556, MR762 Buffer Retainer Pin

    H&K Heckler & Koch

    $3.95
    Heckler and Koch HK416, HK MR556, HK MR762 Buffer Retainer Pin Compatible With: HK416, MR556 HK MR762
    HKP-12704
    $3.95
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    $3.95
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