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 Upper Receiver Kit - 10.4" - Date Coded - OTB - USED
H&K Heckler & Koch
$3,789.95H&K 416 10.4" Date Coded OTB Upper Parts Kit - USED Genuine HK 416 10.4″ date coded used upper parts kit with a factory German 10.4″ barrel with the new Over The Beach (OTB) features (vented gas block, quad rail forearm). Finish...HKP-22193-M$3,789.95 -
HK91, G3 Magazine Release Set - USED
H&K Heckler & Koch
$24.95Heckler and Koch Magazine Release Set (Left to Right) for HK91 and G3 HK-manufactured, used magazine release set for HK .308 pattern rifles. Complete left-to-right mag catch assembly with both push-button and paddle controls. Expect finish wear and...HKP-22466$24.95 -
HK MP5 Case Deflector - 9mm, .40 S&W Receivers
HKP HK Parts
$24.95HKP HK MP5 Case Deflector - 9mm, .40 Receivers US-made steel case deflector for HK MP5 and MP5K receivers in 9mm and .40 S&W. Installs on the ejection-port flat, rivet or weld, to redirect brass and support reliable extraction on MP5 and MP5K style...HKP-22383$24.95 -
HK417, MR762 Enhanced Buffer Tube
H&K Heckler & Koch
$134.95H&K HK MR762/417 Enhanced Buffer Tube/Receiver Extension - Black Brand new factory HK German manufactured MR762, MR308, & HK 417 buffer tube. Compatible With: HK MR762 HK 417HKP-16770$134.95 -
HK FMP G3 Rear Receiver Section - SURPLUS
FMP HK CONTRACT
$24.95H&K G3 Complete Parkerized Rear Receiver Section without Rear Sight - SURPLUS UNIT CONDITION WILL VARY Steel rear receiver section manufactured by FMP on HK tooling. Does not include the rear sight. Compatible with: HK G3, HK91 In-spec...HKP-22375$24.95 -
HK416 E1, MR556 Charging Handle - Incomplete
H&K Heckler & Koch
$109.95HK MR556, HK 416 E1/E2 Charging Handle - Incomplete New HK German manufactured HK MR556, HK 416. A great item to have on hand in the event of breakage or high wear. Compatible With: HK MR556 HK 416 HK M27HKP-17540$109.95 -
HK MR762 A4 Charging Handle
H&K Heckler & Koch
$199.95H&K MR762 A4 Charging Handle Upgrade your MR762 or HK417 style rifle with this factory H&K ambidextrous charging handle, engineered for smooth, reliable operation from either side. Built to Heckler & Koch’s exacting standards, this...HKP-21967$199.95 -
HK G3 - FMP Early Type Demilled Front End
FMP HK CONTRACT
$99.95HK G3 - FMP Early Type Demilled Front End Early style G3 front end with no hanger. These are the perfect option for those doing custom builds. Good condition over all. Includes: Cocking tube Complete cocking handle assembly Trunnion Barrel pinHKP-20845$99.95 -
Out Of Stock
HK91, G3, PSG1, MSG90 T-Rail Reinforcement Set for Receiver
Michaels Machines
$299.95HK Receiver Reinforcement T-Rail Set For Left and Right Sides T-rails are used to strengthen HK receivers or for custom builds. These are the finest T-rails available on the market. Made from enhanced steel and perfect for that custom HK project...HKP-00236$299.95 -
Out Of Stock
HK MP5, HK94 Trunnion - 9mm - USA
HKP HK Parts
$54.95HKP MP5, 94 Trunnion 9mm - USA US made to exact factory HK specifications for the HK MP5, 94 type builds. Machined completely from ordnance grade steel and heat treated to factory specs. These are the best USA made trunnions on the market. Machined to HK...HKP-17934$54.95 -
HK416, MR556 Upper Receiver - Stripped - No Forward Assist
H&K Heckler & Koch
$489.99HK416, MR556 Upper Receiver - Stripped - No Forward Assist Genuine HK HK416 upper receiver designed for HK416 and MR556 rifle platforms. This stripped receiver does not include a forward assist or ejection port door. Compatible With HK416, MR556 MR223HKP-22506$489.99 -
HK MR762 A4 Buffer Tube
H&K Heckler & Koch
$95.95H&K MR762 A4 Buffer Tube Factory German-made buffer tube for the MR762 A4. Compatible With: HK MR762 A1/A4HKP-21964$95.95