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
HK416 A1 Upper Receiver - 10.4"
H&K Heckler & Koch
Now: $2,999.95Was: $3,499.95HK416 10.4" Complete Upper Receiver 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 Tactical. Compatible With: HK416HKP-22245Now: $2,999.95Was: $3,499.95 -
HK417, MR762 Charging Handle Pin
H&K Heckler & Koch
$6.95H&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: HK MR762 HK 417HKP-16754$6.95 -
Out Of Stock
HK21 T-Rail Set - Factory Style
Michaels Machines
$275.00Michael'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 -
Out Of Stock
HK417, MR762 Cylindrical Pin for Stop Pin
H&K Heckler & Koch
$9.95H&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 417HKP-16619$9.95 -
HK G36 Cocking Handle Bushing
H&K Heckler & Koch
$9.95HK German G36 Cocking Handle BushingHKP-01869$9.95 -
HK MP5K Receiver Flat - .40 S&W, 10mm
HKP HK Parts
$199.95MP5K-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***HKP-18033$199.95 -
Out Of Stock
HK G36, SL8 Roll Pin - Gas Piston
H&K Heckler & Koch
$9.95H&K HK G36, HK SL8 Roll Pin for Gas PistonHKP-16386$9.95 -
HK G36, SL8 Cocking Handle
HKP HK Parts
$49.95Cocking 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 -
On Sale
AR-15 Commercial Buffer Tube Kit
HKP HK Parts
Now: $27.95Was: $47.95AR-15 Commercial Buffer Tube Kit Compatible With: All AR-15 style platforms Not correct length for HK rifles Includes: Made with T7 7075 aircraft-grade aluminum Made in the USA with a polished inside tube Mil-Spec triple hard coat Teflon...HKP-02736Now: $27.95Was: $47.95 -
On Sale
HK MP5 Trunnion - Gunsmith Special
USA
Now: $24.95Was: $54.95HK 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...HKP-99089Now: $24.95Was: $54.95 -
HK417, MR762 Charging Handle Catch
H&K Heckler & Koch
$59.95HK MR762, HK417 Extended Charging Handle Catch Complete New HK German manufacture. A great part to have on hand as these are prone to breakage and wear. Compatible With: HK MR762 HK 417 HK G28HKP-16852$59.95 -
HK417, MR762 Ejection Port Cover
H&K Heckler & Koch
$42.95H&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 firearmsHKP-16598-M$42.95