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
    Used - H&K G3 Complete Parkerized Rear Receiver Section w/ Rear Sight - SURPLUS - HKP-22164 HK G3 Rear Receiver Section with Rear Sight - Complete - Parkerized - SURPLUS
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    HK G3 Rear Receiver Section with Rear Sight - Complete - Parkerized - SURPLUS

    H&K Heckler & Koch

    Now: $49.46
    Was: $54.95
    H&K G3 Complete Parkerized Rear Receiver Section w/ Rear Sight - SURPLUS UNIT QUALITY MAY VARY - SEE PHOTOS FOR EXAMPLE OF CONDITION RANGE Genuine H&K parkerized steel rear receiver section with fully installed G3 rear sight assembly, two stock...
    Now: $49.46
    Was: $54.95
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    Was: $54.95
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  • On Sale
    New - H&K HK MR762/417 Cylindrical Pin For Stop Pin - HKP-16619
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    HK417, MR762 Cylindrical Pin for Stop Pin

    H&K Heckler & Koch

    Now: $8.96
    Was: $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
    Now: $8.96
    Was: $9.95
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  • On Sale
    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

    Now: $2,249.95
    Was: $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...
    Now: $2,249.95
    Was: $2,499.95
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    Was: $2,499.95
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  • On Sale
    New - H&K MR762 A4 Pivot Pin - HKP-21958 HK417, MR762 Takedown Pin - Front - A4 Style
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    HK417, MR762 Takedown Pin - Front - A4 Style

    H&K Heckler & Koch

    Now: $36.86
    Was: $40.95
    H&K MR762 A4 Receiver Front Takedown Pin German-made factory pivot pin for the MR762 A4.  Will work with A1 models as well. Compatible With: HK MR762 A1 and A4 HK417  
    Now: $36.86
    Was: $40.95
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    Was: $40.95
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  • On Sale
    New - H&K G36 (5.56/.223) Cocking Handle Bushing - HKP-01869
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    HK G36 Bushing - Cocking Handle

    H&K Heckler & Koch

    Now: $8.96
    Was: $9.95
    HK German G36 Cocking Handle Bushing
    Now: $8.96
    Was: $9.95
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  • On Sale
    New - H&K 416A5 RAL 8K Stripped Upper Receiver - HKP-18787 HK416 A5 Stripped Upper Receiver - RAL8000
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    HK416 A5 Stripped Upper Receiver - RAL8000

    H&K Heckler & Koch

    Now: $1,403.96
    Was: $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 HK MR556 HK MR223 Looking for a matching lower for your build?  STS416 A5 LOWER - Specialized...
    Now: $1,403.96
    Was: $1,559.95
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    Now: $1,403.96
    Was: $1,559.95
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  • On Sale
    Flat Bending Jig Set For All HK Style Flats - RENTAL HKP HK Parts HKP-19595-RENTAL HK Receiver Flat Bending Set Jig - RENTAL
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    HK Receiver Flat Bending Set Jig - RENTAL

    HKP HK Parts

    Now: $79.96
    Was: $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...
    Now: $79.96
    Was: $99.95
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    Now: $79.96
    Was: $99.95
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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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    Was: $54.95
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  • Out Of Stock
    On Sale
    New - HKP HK 416 Upper Receiver - HKP-17783 HK416 Upper Receiver

    HK416 Upper Receiver

    HKP HK Parts

    Now: $391.96
    Was: $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...
    Now: $391.96
    Was: $489.95
    Out Of Stock
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    Now: $391.96
    Was: $489.95
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  • New - HKP AR-15 Commercial Buffer Tube Kit - HKP-02736 HKP AR-15 Commercial Buffer Tube Kit HKP HK Parts HKP-02736
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    HK416, MR556, AR-15 Commercial Buffer Tube Kit

    HKP HK Parts

    $47.95
    AR-15 Commercial Buffer Tube Kit Compatible With: HK MR556 & 416  All AR-15 style platforms  Includes: Made with T7 7075 aircraft-grade aluminum Made in the USA with a polished inside tube Mil-Spec triple hard coat Teflon anodized...
    $47.95
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  • On Sale
    New - H&K HK 416 Commercial OTB Buffer Tube HK E1 Stock Combo - Black - hkp-18361 HK416 Commercial OTB Buffer Tube HK E1 Stock Combo
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    HK416 Commercial OTB Buffer Tube HK E1 Stock Combo

    H&K Heckler & Koch

    Now: $422.95
    Was: $469.95
    HK 416 OTB E1 Stock & Buffer Tube Combo - Commercial Genuine HK 416 E1 commercial stock with the new style marine environment "over the beach" buffer tube. Buffer tube has ball bearing rollers to tighten the stock when locked in position, and helps...
    Now: $422.95
    Was: $469.95
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    Now: $422.95
    Was: $469.95
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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
    Was: $24.95
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