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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Out Of Stock
HK416C Upper Receiver Kit - 9"
HKP HK Parts
$2,799.95HK416C Complete Upper Kit - 9" Our complete 416C upper kit includes everything you need to pair with a mil-spec lower or an STS 416C lower. For that genuine look, the STS 416C lower with the correct 416C stock eyelets is as good as you can get...$2,799.95 -
HK MP5K, SP89 Flat Receiver - 9mm
HKP HK Parts
$199.95MP5K, SP89 Receiver Flat - 9mm New MP5K receiver flat made by the original German tool and die maker of the LSC receiver flat utilizing factory original German prints and specifications. The creator of our receiver flat has been regarded as the premier...$199.95 -
HK417, MR762, G28 Receiver End Plate
H&K Heckler & Koch
$24.95H&K HK MR762/417/G28 Receiver End Plate New HK German factory. Compatible With: HK MR762 HK 417 HK G28$24.95 -
HK MP5 Rear Receiver Section
H&K Heckler & Koch
$14.95H&K MP5 Rear Receiver Section HK German demilled receiver section with rear sight base as installed at the factory. MP5 & HK94 Factory HK rear sight bases (portion welded to MP5 receiver), you get the actual demilled section of an MP5 receiver...$14.95 -
HK MP5, MP5K Scope Tab - Billeted - Weldment
HKP HK Parts
$9.95HKP 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$9.95 -
HK416, HK417, MR556, MR762 Takedown Pin - Rear - A4 Style
H&K Heckler & Koch
$43.95H&K MR556, HK416, HK417, MR762 Rear Takedown Pin Factory A4 rear takedown pin. Will work for A1 and A4 applications. Compatible With: HK MR556 A1 and A4 HK416 HK MR762 A1 and A4 HK417 AR-14, M4, M16$43.95 -
$14.95 -
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.$275.00 -
HK MR762 Ejection Door Clamping Sleeve
H&K Heckler & Koch
$4.95H&K HK MR762 Ejection Door Clamping Sleeve Compatible With: HK MR762$4.95 -
HK417, MR762 Upper Receiver Rod Tool
MI Midwest Industries
$159.95Midwest 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...$159.95 -
On Sale
HK MP5K Trunnion - Gunsmith Special
USA
Now: $18.71Was: $54.95HK 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: $18.71Was: $54.95 -
MM HK PSG1/21E/23E Forward Complete Assist Assembly
Michaels Machines
$779.95MM 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...$779.95