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
HK MP5 Receiver Flat - .40 S&W, 10mm
HKP HK Parts
Now: $194.95Was: $399.95MP5 40 & MP5 10mm Receiver Flat - USA The new and latest production with the weldment locations is already lasered and ready to go. This flat is the finest available for the MP5 40/10 family of firearms. Compatible With: MP5 .40 Cal MP5 10mm MP5 ...HKP-00767Now: $194.95Was: $399.95 -
Out Of Stock
HK MP5 1913 End Plate Adapter
MI Midwest Industries
$89.95MI HK MP5 1913 End Plate Adapter The Midwest Industries Picatinny end plate adapter opens up your stock and brace options to a myriad of off-the-shelf possibilities. The adapter installs in the same manner as the factory end cap with a single push pin...HKP-21493$89.95 -
HK SL8, G36 Magazine Release Axle Pin
GSG9
$10.95GSG9 Magazine Release Axle - USA made for HK G36 and HK SL8 Mag release axle for all G36 and SL8 models. A must-have spare part. Made in the USA. Compatible With: G36 G36K SL8 Other custom G36 type buildsHKP-18255$10.95 -
HK SP5K 9mm Drop In Paddle Mag Release Upgrade Kit
H&K Heckler & Koch
$129.95HKP HK Parts and Heckler and Koch Anti-Rattle Roller Tipped Paddle Magazine Release Kit No modifications, no refinishing...complete drop-in kit included New HK German and USA made paddle mag release kit for the HK SP5K. This kit will allow any...HKP-18082$129.95 -
HK416, MR556 Takedown Pin - Front - A1 Style
H&K Heckler & Koch
$64.95H&K HK MR556 Front Lower Receiver Locking Pin With Spring Loaded Detent This part is the front (large) takedown pin with ball detent and locking mechanism installed. The idea behind this type of system is to decrease the movement of the upper and...HKP-02663$64.95 -
HK MP5 Receiver Flat- 9mm
LSC
$239.95MP5 Receiver Flat - PTR/LSC New PTR 9mm Receiver Flat made on the original LSC tooling. This flat is considered by many to be the most sought-after HK flat available on the market and perfect for that HK custom build. This item is not considered an FFL...HKP-01431$239.95 -
Out Of Stock
HK SP5 Case Deflector - 9mm, 10mm, .40 S&W
H&K Heckler & Koch
$49.95Heckler and Koch Case Deflector for 9mm, 10mm, and .40 S&W HK SP5 Factory HK case deflector for the SP5 platform chambered in 9mm, 10mm, and .40 S&W. Compatible With: SP5HKP-02170$49.95 -
HK MR556 Incomplete Upper Receiver
H&K Heckler & Koch
$449.95HK German Stripped HK MR556 Upper Receiver New factory German incomplete and unmarked MR556 upper receiver. Compatible With: HK MR556 HK MR223 HK 416 Do you need a matching lower for your build? STS416 A5 LOWER - Specialized Tactical...HKP-02615$449.95 -
Out Of Stock
HK416, MR556 Ejection Port Cover Assembly
H&K Heckler & Koch
$89.95HK German HK 416, MR556 Ejection Port Cover Door Assembly Complete This is the newer polymer style cover found on the latest HK 416 and MR556's. This is the complete ejection port door assembly needed on all AR15 or MR556/HK416 models. Can also be used...HKP-16951$89.95 -
PTR Spec Tac Latch
Other
$69.95Tac Latch (latest Generation) PTR Spec - PTR .308 Firearms The new updated style of Tac latch is made specifically for the PTR 91 .308 receiver and will require very little modification to the firearm for installation. A major overhaul of the existing...HKP-17611$69.95 -
HK416, MR556, MR762 Forward Assist Assembly, Complete
H&K Heckler & Koch
$74.95H&K Heckler and Koch Forward Assist Assembly for HK416, HK MR556, and HK MR762 H&K Germany factory HK MR556 and HK416 forward assist assembly complete. Compatible With: HK 416, MR556 HK MR762HKP-16528$74.95 -
HK MP5F Receiver Flat - Alternate Holes
HKP HK Parts
$125.95HKP HK MP5F 9mm Flat - Alternate Holes MP5 receiver flat crafted by the original German tool and die maker of the LSC receiver flat using factory original German prints and specifications. This receiver features alternate holes for the correct MP5F or...HKP-21551$125.95