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 with Weldment Set - 9mm
HKP HK Parts
$219.95HKP HK MP5 9mm Receiver Flat with Weldment Set New MP5 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-20920$219.95 -
HK416, MR556, MR762 Buffer Retainer Pin
H&K Heckler & Koch
$3.95H&K HK MR556/MR762/416 Buffer Retainer Pin Compatible With: HK MR556 HK 416HKP-12704$3.95 -
HK416, MR556 Ejection Port Cover
H&K Heckler & Koch
$55.95H&K HK MR556/416 Ejection Port Cover HK manufactured newer polymer style cover assembly found on the latest HK 416 & MR556. This item can also be used on other AR15-style projects to enhance the project with the finest ejection port cover...HKP-15229$55.95 -
HK MP5 Receiver Flat with Weldment Set
PTR
$294.95MP5 9mm Receiver Flat With Complete Weldment & Rivet Set - PTR/LSC Several years ago PTR bought out LSC and now owns the tooling and dyes for the LSC 9mm flats. These elusive flats have been hard to find and are now available for the first time here...HKP-19509$294.95 -
HK MP5 Trunnion - 9mm
RCM
$64.95RCM MP5 9mm Trunnion US made to exact factory HK specifications and machined completely from ordnance grade steel and heat treated to factory specs. Compatible With: MP5, 94 MP5K SP89 Clones or other custom buildsHKP-01193$64.95 -
HK416, HK417, MR556, MR762 Buffer Retaining Pin
H&K Heckler & Koch
$15.95H&K HK MR556/MR762/416/417 Buffer Retaining Pin New HK German proprietary HK designed buffer pin unique to the HK 416 and MR 556 series. Compatible With: HK MR556 HK 416 HK MR762 HK M27HKP-02544$15.95 -
HK91, G3 Mag Release Set
H&K Heckler & Koch
$34.95Heckler and Koch Magazine Release Set (Left to Right) for HK91, G3 This magazine catch set consists of 4 pieces and is HK-manufactured. Includes: Magazine Catch Magazine Catch Spring Push Button Clamping Sleeve to retain Push Button Compatible...HKP-00929$34.95 -
HK SL8, G36 Extended Mag Release
H&K Heckler & Koch
$19.95HK SL8 & G36 Oversized Extended Mag Release New HK German SL8, G36, HK243 extended magazine release. A must have upgrade for your HK SL8, Sl8-G36 conversion or G36 firearm. The HK extended magazine release is a drop in replacement and requires zero...HKP-17720$19.95 -
HK MP5, MP5K Cartridge Case Deflector, Shell Deflector - Billet
HKP HK Parts
$19.95Cartridge Case Deflector, Shell Deflector - MP5, MP5K - Billet New US made case deflector for receiver flat or receiver for all MP5, HK94, MP5K, & SP89 builds. The case deflector is riveted or welded in place on the ejection port of the 9mm receiver...HKP-17574$19.95 -
HK MP5 Magazine Release - Extended - EMR - Streamline
HKP HK Parts
$44.95HKP HK MP5 Extended Magazine Release - EMR - Streamline Elevate your paddle style mag release with the streamlined extended mag release. Crafted from a solid billet of aircraft-grade aluminum and featuring a hard anodized finish, this lightweight...HKP-22175-M$44.95 -
HK G3/HK91 Anti-Rattle Mag Release - Surplus
H&K Heckler & Koch
$24.95H&K HK G3, HK 91, PTR, HK 93, HK 53, HK 33 Anti-Rattle Mag Release - Surplus Pulled from demilled German HK firearms. Once refinished this item can be made to look like new. For install on all HK .223 & .308 HK Rifles. This is the highly desired...HKP-17855$24.95 -
HK416, HK417, MR556, MR762 Takedown Pin Detent Spring
H&K Heckler & Koch
$9.95H&K HK MR556/MR762/416/417 Takedown Pin Detent Spring New HK German manufacture. Detent spring for the rear takedown pin. Compatible With: HK MR556 HK 416 HK MR762 HK 417HKP-02541$9.95