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
HK UMP, USC Conversion Slide
H&K Heckler & Koch
$19.95HK USC & UMP Slide For Lower - German New HK German USC slide for conversion of UMP lower.HKP-00268$19.95 -
HK Mark 23 Magazine Release Spring
H&K Heckler & Koch
$10.95HK Mark 23 Magazine Release SpringHKP-01789$10.95 -
Out Of Stock
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...HKP-00852$779.95 -
HK CC9 Magazine Release & Chassis Pin
H&K Heckler & Koch
$5.95H&K CC9 Magazine Release & Chassis Pin Made by H&K, this authentic pin for the CC9 secures magazine release and chassis components within the frame. Compatible With: HK CC9HKP-22112$5.95 -
$7.95 -
HK33, HK53, HK93, HK91, G3 Anti-Rattle Mag Release
H&K Heckler & Koch
$64.95HK German Anti Rattle Paddle Magazine Release This item is a new H&K genuine part not used or surplus for installation on all HK .223 & .308 HK Rrifles. This is the highly desired anti-rattle-style paddle mag release. Compatible With: HK 91 HK...HKP-01126$64.95 -
HK MR762 A4 Upper Receiver Kit - 13"
H&K Heckler & Koch
$2,499.95HK 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...HKP-22399$2,499.95 -
On Sale
HK MP5K Trunnion - Gunsmith Special
USA
Now: $24.95Was: $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...HKP-99090Now: $24.95Was: $54.95 -
HK USC Magazine Release Axle - .45 ACP
H&K Heckler & Koch
$18.95Heckler and Koch USC .45 ACP Magazine Release Axle Replacement magazine release axle for HK USC .45 ACP platforms. This component is commonly replaced due to wear or breakage and may also be required when configuring compliant magazine release systems...HKP-02584$18.95 -
Out Of Stock
HK33, HK53, HK93 Magazine Catch - Latest Design
H&K Heckler & Koch
$49.95Heckler and Koch German Factory Magazine Catch for HK33, HK53, HK93 New HK German 93,33,53 mag catch for magazine release. Compatible With: HK93 HK33 HK53 HK33K Clone or other custom buildsHKP-01059$49.95 -
HK MR762 Ejection Door Clamping Sleeve
H&K Heckler & Koch
$4.95H&K HK MR762 Ejection Door Clamping Sleeve Compatible With: HK MR762HKP-16518$4.95 -
HK UMP Paddle Magazine Release - Extended
HKP HK Parts
$34.95UMP Paddle Magazine Release - Extended Billeted alloy UMP magazine release. This is a very common repair & replacement part as they are fairly easy to break on the UMP lower. With this new metal mag release you get more surface area as well as a much...HKP-17919$34.95