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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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, .40 S&W / 10mm
H&K Heckler & Koch
$49.95SP5 Case Deflector - 9/10/40 Factory HK case deflector for the SP5 platform chambered in 9mm, 10mm, and .40 S&W. Compatible With: H&K SP5 9/10/40HKP-02170$49.95 -
Out Of Stock
HK416, MR556 Castle Nut
H&K Heckler & Koch
$32.95H&K HK MR556/416 Castle Nut For Buffer Tube New HK German manufacture. This buffer tube castle nut will fit both mil-spec and commercial buffer tubes. All steel manufacture. With HK round tool attachment points as well as traditional wrench...HKP-15230$32.95 -
HK SL8, G36 Magazine Release Axle Pin
GSG9
$10.95HK G36 & SL8 Magazine Release Axle - USA Mag release axle for all G36 & SL8 models. A must-have spare part. Made in the USA. Compatible With: G36 G36K G36K SL8 Other custom G36 type buildsHKP-18255$10.95 -
HK SP5K 9mm Drop In Paddle Mag Release Upgrade Kit
H&K Heckler & Koch
$129.95German HK SP5K Anti-Rattle Roller Tipped Paddle Magazine Release Kit No modifications, no refinishing...complete drop-in kit included New HK German & USA made paddle mag release kit for the HK SP5K. This kit will allow any end-user to quickly...HKP-18082$129.95 -
HK MP5 Magazine Release Set
H&K Heckler & Koch
$184.95H&K Magazine Release Set This is the complete magazine release kit that includes both the paddle mag release and standard left-to-right mag release on your HK 9mm rifle or pistol build. Compatible With: MP5, MP5K style 9mm models Set...HKP-02402$184.95 -
HK91, G3, HK33, HK93 Bayonet Adapter - Complete - Turkish Contract
Other
$38.95Turkish Contract Complete Bayonet Adapter for HK91, HK G3, HK33, HK93 Complete Turkish contract 90 Series-style steel bayonet adapter supplied with the required mounting hardware. Designed for proper fit on HK33, HK93, HK91, and G3 pattern rifles...HKP-22517$38.95 -
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 -
Out Of Stock
HK416, MR556 Ejection Port Cover Door 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 -
HK USP, USP Compact, P2000 Magazine Release Lever
H&K Heckler & Koch
$12.95HK Magazine Release Lever Compatible With: HK USP .45 HK USP .40 HK USP 9mm HK USP Compact 9mm HK USP Compact .357 SIG HK USP Compact .40 HK USP Compact .45 HK USP Tactical, Elite, Expert both full size & compact HK P2000 9mm & .40/.357 HK...HKP-02480$12.95 -
Picatinny Rail for HK Receivers - 15 Slot
DTAC Dakota Tactical
$74.95Dakota Tactical Picatinny Rail To Weld To The Receiver Mil-Spec all steel picatinny rail in the white, relief cut for HK receivers & made for mounting scopes and optics to HK builds. This unit easily welds to the top of your HK receiver. Compatible...HKP-17819$74.95 -
HK MP5, MP5K, G36, HK33, HKK53, HK93, HK417 Magazine Release Bushing - Full Auto
MKE
$2.59MKE HK MP5/MP5K Magazine Release Bushing This part is for use in all 90-series H&K weapon systems and is used for installing a paddle mag release. This is not for use on semi-auto HK builds. This part is intended for full-auto conversions only...HKP-22283$2.59