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 MR762/417/G28 E1 Extended Ambidextrous Charging Handle - Black - HKP-16599 HK417, MR762, G28 E1 Charging Handle - Extended - Ambidextrous
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    HK417, MR762, G28 E1 Charging Handle - Extended - Ambidextrous

    H&K Heckler & Koch

    Now: $188.95
    Was: $209.95
    H&K HK MR762/417/G28 E1 Extended Ambidextrous Charging Handle HK German MR762/HK 417 extended charging handle. The unique release latch can be swapped from left to right sides to make each setup ambi friendly and modular. HK's own design boasts an...
    Now: $188.95
    Was: $209.95
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    New - HKP HK MP5/K Billeted Scope Tab - Weldment - HKP-22063
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    HK MP5, MP5K Scope Tab - Billeted - Weldment

    HKP HK Parts

    Now: $7.96
    Was: $9.95
    HKP HK MP5/K Billeted Scope Tab - Weldment Billeted scope tab weldment for HK MP5, MP5K, and compatible clones. Provides a correct mounting point for optics. Compatible With: HK MP5/94 HK MP5K/SP89 HK MP5 40/10 Clones or custom builds
    Now: $7.96
    Was: $9.95
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    New - HK MP5K Side Reinforcement Tabs - HKP-20168 HK MP5K Side Reinforcement Tabs
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    HK MP5K Side Reinforcement Tabs

    USA

    Now: $13.46
    Was: $14.95
    HK MP5K Side Reinforcement Tabs
    Now: $13.46
    Was: $14.95
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    HK417, MR762 Upper Receiver Rod Tool HK417, MR762 Upper Receiver Rod Tool

    HK417, MR762 Upper Receiver Rod Tool

    MI Midwest Industries

    Now: $143.95
    Was: $159.95
    Midwest Industries Upper Receiver Rod Tool for HK417, MR762 Receiver support rod for HK417 and MR762 upper receivers. Designed to prevent receiver and index-pin damage during barrel nut removal, muzzle device installation, and other high-torque...
    Now: $143.95
    Was: $159.95
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    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

    Now: $247.50
    Was: $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.  
    Now: $247.50
    Was: $275.00
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    Now: $247.50
    Was: $275.00
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    New - H&K HK MR762 Ejection Door Clamping Sleeve - HKP-16518
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    HK MR762 Ejection Door Clamping Sleeve

    H&K Heckler & Koch

    Now: $4.46
    Was: $4.95
    H&K HK MR762 Ejection Door Clamping Sleeve Compatible With: HK MR762
    Now: $4.46
    Was: $4.95
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  • On Sale
    New - HK MP5K Trunnion - Gunsmith Special - HKP-99090 HK MP5K Trunnion - Gunsmith Special
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    HK MP5K Trunnion - Gunsmith Special

    USA

    Now: $18.71
    Was: $54.95
    HK MP5K 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: $18.71
    Was: $54.95
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  • On Sale
    New - H&K 416 Front Takedown Pin - HKP-21862 HK416, MR556 - Takedown Pin - Front - A4 Style
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    HK416, MR556 - Takedown Pin - Front - A4 Style

    H&K Heckler & Koch

    Now: $24.25
    Was: $26.95
    H&K HK416, MR556 A4 Front Takedown Pin  The HK416 front takedown pin is a German-made component designed to securely fasten the upper and lower receivers. Precision-machined for a proper fit, it ensures reliable function and serves as an ideal...
    Now: $24.25
    Was: $26.95
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    New - H&K HK G36, HK SL8 Roll Pin for Gas Piston - Black - HKP-16386

    HK G36, SL8 Roll Pin - Gas Piston

    H&K Heckler & Koch

    Now: $8.96
    Was: $9.95
    H&K HK G36, HK SL8 Roll Pin for Gas Piston
    Now: $8.96
    Was: $9.95
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  • On Sale
    New - HKP HK G36/SL8 (5.56/.223) Cocking Handle - HKP-18251 HK G36, SL8 Cocking Handle
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    HK G36, SL8 Cocking Handle

    HKP HK Parts

    Now: $39.96
    Was: $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.
    Now: $39.96
    Was: $49.95
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  • On Sale
    New - MM HK PSG1/21E/23E Forward Complete Assist Assembly - HKP-00852 MM HK PSG1/21E/23E Forward Complete Assist Assembly
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    MM HK PSG1/21E/23E Forward Complete Assist Assembly

    Michaels Machines

    Now: $701.96
    Was: $779.95
    MM HK PSG1/21E/23E Forward Complete Assist Assembly Michael's Machines US-made complete forward assembly or your HK PSG1, MSG90, HK21E/23E.  A great option for a build now that the factory units are no longer available.  Available exclusively...
    Now: $701.96
    Was: $779.95
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    Was: $779.95
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  • On Sale
    New - HKP MP5K 40/10 Receiver Flat - HKP-18033 HK MP5K Receiver Flat - 10mm / .40 S&W -
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    HK MP5K Receiver Flat - 10mm / .40 S&W -

    HKP HK Parts

    Now: $159.96
    Was: $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 flat counts as one required 922r compliant part***
    Now: $159.96
    Was: $199.95
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