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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HK416, MR556 Ejector Port Cover Pin
H&K Heckler & Koch
$19.95HK MR556 & 416 Ejector Port Cover Pin Compatible With: HK MR556 HK 416HKP-02661$19.95 -
HK SL8, G36 Magazine Release Spring - US
GSG9
$4.95HK G36 & SL8 Magazine Release Spring - USA Mag release spring for all G36 & Sl8 models. A must have spare part. Made in the USA. G36 G36K G36K SL8 Other custom G36 type buildsHKP-18254$4.95 -
HK G36 Backplate
H&K Heckler & Koch
$94.99HK G36 Backplate With Recoil Buffer This is a great spare or replacement to have on hand. These are also required for those that are doing the SL8-G36 conversions provided by Tommy Bostic & Chopstix Kid.HKP-01058$94.99 -
HK MP5 Receiver Flat - 9mm
HKP HK Parts
$189.95HKP HK MP5 9mm Receiver Flat New MP5 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 flat...HKP-20921$189.95 -
HK UMP, USC Magazine Release Spring
H&K Heckler & Koch
$9.95HK UMP & USC Magazine Release Spring HK German factory mag release spring for all USC and UMP mag releases. Compatible With: USC lowers UMP lowersHKP-01899$9.95 -
HK91, G3, HK33, HK53, HK93 Contact Piece for Paddle Mag Release
H&K Heckler & Koch
$29.95HK .223/556 & 308 Contact Piece For Paddle Magazine Release German HK manufacture. The contact piece is used in the magazine release assembly for the paddle mag release. Compatible With: HK 33, 53, 93 HK G3, 91, PTR91HKP-00465$29.95 -
HK MP5K, SP89 Receiver Flat with Weldment Set
HKP HK Parts
$239.95HKP - MP5K, SP89 Receiver Flat With Weldment Set New MP5K receiver flat and weldment set combined for the best complete build option on the market. Made by the original German tool and die maker of the LSC receiver flat utilizing factory original German...HKP-20882$239.95 -
HK VP9B Push Button Mag Release Tool
H&K Heckler & Koch
$17.99Push Button Mag Release Disassembly Tool - HK VP9 B The factory HK OEM tool used to change the left to right mag release button of the VP9B models. Compatible With: HK VP9B NOT compatible with VP9A1 F, VP9A1 KHKP-19747$17.99 -
HK USC Magazine Release - .45 ACP
H&K Heckler & Koch
$19.95H&K USC (.45 ACP) Carbine Mag Release This is a great replacement as they are prone to breakage & wear. Please Note: For those that have a USC with a bullet button and are moving to a free state and want to revert back to the...HKP-02196$19.95 -
HK416A5 Stripped Upper Receiver
H&K Heckler & Koch
$489.99HK 416A5 - Stripped Upper Receiver This is the factory correct receiver for a true 416 build as it features the M16 relief cut in the bottom, rear portion of the receiver (shown in last pricture). Compatible With: HK 416 HK MR223 HK MR556 Need a...HKP-18786$489.99 -
HK G36 Backplate Complete w/ Recoil Assembly
USA
$84.95HK G36 Backplate Complete With Recoil Assembly New G36 Backplate with new G36/SL8 recoil buffer and recoil assembly. This assembly does include the recoil rod retaining screw. This is a great spare or replacement to have on hand. These are also required...HKP-18537$84.95 -
HK SL8, G36 Magazine Release Spring
H&K Heckler & Koch
$9.95HK German G36 & SL8 Magazine Release Spring A must have spare part. Compatible With: G36 SL8HKP-16344$9.95