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 416A5 RAL 8K Stripped Upper Receiver - HKP-18787 HK 416A5 Stripped Upper Receiver - RAL8000
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    HK 416A5 Stripped Upper Receiver - RAL8000

    H&K Heckler & Koch

    $1,559.95
    HK German Un-Assembled Stripped HK 416A5 Upper Receiver - RAL 8K Brand new factory German RAL 8000 416A5 upper receiver. Compatible With: HK416 HK MR556 HK MR223 Looking for a matching lower for your build?  STS416 A5 LOWER - Specialized Tactical...
    $1,559.95
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  • Out Of Stock
    New - HKP HK 416 Upper Receiver - HKP-17783 HK416 Upper Receiver

    HK416 Upper Receiver

    HKP HK Parts

    $489.95
    US Made Complete HK 416, MR556 Style Upper Receiver New US made HK416/MR556 style upper receiver.  Includes: Upper receiver Forward assist assembly Ejection port door assembly Piston guide Compatible With: HK MR556 HK MR223 HK 416 Need a...
    $489.95
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    $489.95
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  • HK MR762 A4 Upper Receiver Kit - 13" HK MR762 A4 Upper Receiver Kit - 13"
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    HK MR762 A4 Upper Receiver Kit - 13"

    H&K Heckler & Koch

    $2,499.95
    HK MR762 A4 Upper Receiver Kit - 13" The MR762 A4 kit contains a complete upper receiver and barrel assembly. The closed system design significantly reduces malfunctions typically associated with direct-impingement gas systems, as hot carbon fouling and...
    $2,499.95
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  • New - H&K MR762 A4 Pivot Pin - HKP-21958 HK MR762 A4 Pivot Pin
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    HK MR762 A4 Pivot Pin

    H&K Heckler & Koch

    $40.95
    H&K MR762 A4 Pivot Pin German-made factory pivot pin for the MR762 A4. Compatible With: HK MR762 A1/A4  
    $40.95
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  • On Sale
    New - HK MP5 Trunnion - Gunsmith Special - HKP-99089 HK MP5 Trunnion - Gunsmith Special
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    HK MP5 Trunnion - Gunsmith Special

    USA

    Now: $24.95
    Was: $54.95
    HK MP5 Trunnion - Gunsmith Special US made HK MP5 trunnions sold as-is. Will require work before being functional. We recommend the work be performed by a professional gunsmith. The condition will vary from part-to-part vs. the pictured unit. Compatible...
    Now: $24.95
    Was: $54.95
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  • On Sale
    New - H&K HK MR556/416 Receiver End Plate - BLEMISHED - HKP-16603-B HK416, MR556 Receiver End Plate - BLEMISHED
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    HK416, MR556 Receiver End Plate - BLEMISHED

    H&K Heckler & Koch

    Now: $11.21
    Was: $24.95
    H&K HK MR556/416 Receiver End Plate - BLEMISHED INSTALLATION MARKS. COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. New HK German manufacture. Compatible...
    Now: $11.21
    Was: $24.95
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    Now: $11.21
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  • HK417, MR762 Ejection Port Cover
New - H&K HK MR762/417 Ejection Port Cover - HKP-16598
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    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 HK G28 Other HK Spec .308 firearms
    $42.95
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  • Flat Bending Jig Set For All HK Style Flats - RENTAL HKP HK Parts HKP-19595-RENTAL HK Flat Jig Bending Set - Receiver Flats - RENTAL
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    HK Flat Jig Bending Set - Receiver Flats - RENTAL

    HKP HK Parts

    $99.95
    Flat Bending Jig Set For All HK Style Receiver Flats - RENTAL Receiver flat bending jig RENTAL for all HK receiver flats.  Our rental jigs are crafted in the US from billeted steel and include the latest revisions with proper dowel spacing for the...
    $99.95
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  • On Sale
    New - H&K HK416A1 10.4" Upper Receiver Kit - AI Date Code (2008) - PD Trade-In - HKP-22245 H&K HK 416 10.4 - AI Upper H&K Heckler & Koch HKP-22245
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    HK416 A1 Upper Receiver - 10.4"

    H&K Heckler & Koch

    Now: $2,999.95
    Was: $3,499.95
    Heckler and Koch's 10.4" Complete Upper Receiver Kit for your HK416 Features: Factory German 10.4" length (2008) date coded   P.D trade-in de-serialized during the de-milling process.  Finish your build with a matching lower from STS...
    Now: $2,999.95
    Was: $3,499.95
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    Now: $2,999.95
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  • Used - H&K 416 10.4" Date Coded OTB Upper Receiver Kit - USED - HKP-22193-M HK416 Upper Receiver Kit - 10.4" - Date Coded - OTB - USED
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    HK416 Upper Receiver Kit - 10.4" - Date Coded - OTB - USED

    H&K Heckler & Koch

    $3,789.95
    H&K 416 10.4" Date Coded OTB Upper Parts Kit - USED Genuine HK 416 10.4″ date coded used upper parts kit with a factory German 10.4″ barrel with the new Over The Beach (OTB) features (vented gas block, quad rail forearm).  Finish...
    $3,789.95
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    $3,789.95
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  • Used - HK G3 - FMP Early Type Demilled Front End - HKP-20845 HK G3 - FMP Early Type Demilled Front End
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    HK G3 - FMP Early Type Demilled Front End

    FMP HK CONTRACT

    $99.95
    HK G3 - FMP Early Type Demilled Front End Early style G3 front end with no hanger. These are the perfect option for those doing custom builds. Good condition over all. Includes: Cocking tube Complete cocking handle assembly Trunnion Barrel pin
    $99.95
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  • Out Of Stock
    New - MM HK PSG1/MSG90/91/G3 (7.62x51/.308) T-Rail Reinforcement Set For Receiver - HKP-00236

    HK91, G3, PSG1, MSG90 T-Rail Reinforcement Set for Receiver

    Michaels Machines

    $299.95
    HK Receiver Reinforcement T-Rail Set For Left and Right Sides T-rails are used to strengthen HK receivers or for custom builds. These are the finest T-rails available on the market. Made from enhanced steel and perfect for that custom HK project...
    $299.95
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