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 Buffer Tube - Mil-Spec
HKP HK Parts
$29.95Mil-Spec US-Made Buffer Tube Compatible With: HK416 HK MR556 All AR-15 style platforms Features: Made from T7 7075 aircraft grade aluminum 6-position Made in the USA Each features a highly polished inside tube Black mil-spec triple hard coat teflon...HKP-02727$29.95 -
Out Of Stock
HK 416, MR556 Castle Nut - A5 Style - Extended
HKP HK Parts
$39.95HK 416, MR556 A5 Style Extended Length Castle Nut Unlike the factory German A5 castle, our A5 extended buffer tube castle nut is compatible with both mil-spec & commercial buffer tubes. Crafted from ordnance grade steel and nitrided for a...HKP-18058$39.95 -
HK UMP, USC 9mm / .40 S&W / .45 ACP Enhanced Top Receiver Rail
HKP HK Parts
$49.95HK USC & UMP Top Receiver Rail With Hardware - US Made The extended length allows the use of all optics that fit on a Picatinny rail. This unit has a contoured, no-snag design for ease of use and a beautiful fit. Made from billet machined aluminum...HKP-14541$49.95 -
UZI Lower with Grip Complete
IMI
$99.95Uzi Lower Complete - IMI Manufactured For The German Military Surplus IMI Manufactured Uzi Grip (lower) complete with all internals as shown. Each lower comes complete with all internals, grips and mag release assembly installed. Perfect for spare parts...HKP-16683$99.95 -
HK MP5, MP5K Magazine Release - 4-Piece Set
HKP HK Parts
$79.95HKP HK MP5/MP5K 4-Piece Set Magazine Release Each magazine catch set consists of 4 pieces and is a mixture of German HK and US-made parts. This is the set that provides left-to-right mag release controls. Each Set Includes: Mag catch (German) Push...HKP-00912$79.95 -
Out Of Stock
HK MP5, MP5K Contact Piece for Paddle Mag Release - 9mm - US
HKP HK Parts
$15.95HK MP5, MP5K 9mm Contact Piece - USA Factory correct US manufactured MP5, MP5K 9mm Contact Piece for Paddle magazine release. Each part was made using the same material and manufacturing methods used on the German HK latest production parts. Hard to find...HKP-17403$15.95 -
HK417, MR762, G28 Buffer Tube Wrench
HKP HK Parts
$29.95HKP HK MR762/417/G28 Buffer Tube Wrench The perfect metric wrench to remove and install the MR762 & G28 castle nuts on the buffer tube. A perfect addition to have on hand for G28 buffer tube upgrades, etc. Made from all steel, heat treated and made...HKP-17111$29.95 -
HK MP5, HK94 Complete Weldment Set For Receiver Flat
HKP HK Parts
$59.95HKP MP5/HK94 Complete Weldment Set For Receiver Flat This is the finest, most correct weldment set for your HK MP5, 94 project available. Each Weldment Kit Contains: 1x Semi Auto Shelf Hanger Block 1x Rear stock bushing 1x Scope mounting piece 1x...HKP-01453$59.95 -
HK Receiver Flat Bending Jig Set - Billet Steel
HKP HK Parts
$599.95Flat Bending Jig Set For All HK Style Flats - Billeted - All Steel All steel billeted universal flat bending jig for all HK receiver flats including PTR .308 flats and the PTR/LSC flats. Each bending jig comes complete with all the pieces you need for...HKP-19595$599.95 -
HK VP9, VP40 Enhanced Magazine Release
HKP HK Parts
$49.95Enhanced Magazine Release - Alloy - HK VP Series The oversized magazine release increases the overall surface area and makes it possible to release the magazine without changing the position of your grip. Made in the USA from 6061 billeted aluminum...HKP-21099-M$49.95 -
Out Of Stock
HK MP5, MP5K 9mm Anti-Rattle Roller Tipped Paddle Magazine Release
HKP HK Parts
$29.47HK MP5, MP5K 9mm Anti-Rattle Roller Tipped Paddle Magazine Release Latest generation paddle mag release for all 9mm MP5, MP5K style builds. Made to the latest German specs, materials, and design. Compatible With: MP5, 94 MP5K, SP89, SP5K Other...HKP-17570$29.47 -
HK UMP Lower Locking Pin
HKP HK Parts
$12.95HK UMP Lower Locking Pin, Push Pin For use with all HK UMP lowers & USC to UMP conversions. Made in the USA. This is the pin that holds the lower to the receiver. Compatible With: UMP USC Conversions TBT builds Omega Other builds that...HKP-18580$12.95