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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B&T MP5 Mount For Trijicon 1X24 Reflex
B&T Brugger & Thomet
$152.95B&T MP5 Mount for Trijicon 1X24 Reflex Low profile mount for HK MP5 with Trijicon RX01m 1x24 Specifications: Color: Black Width max: 42.5 mm Length max: 125.5 mm Height max: 25.8 mm Material: Aluminum & steel Treatment: Hartcoat anodized &...HKP-16863$152.95 -
Out Of Stock
H&K HK G36 Sight Rail w/ Mechanical Sights - Black
H&K Heckler & Koch
$0.00Sight Rail with Mechanical Sights - G36 Low profile rail with built-in mechanical sights. Made from aluminum. Overall length 18". Compatible With: G36 G36K G36CHKP-18729$0.00 -
H&K HK G36/SL8 New Style Scope Rail HK German - Black
H&K Heckler & Koch
$244.95HK German HK SL8 & G36 Picatinny Scope With Rail/ Carry Handle This is the perfect mounting solution for optics. Made from the highest quality combat grade aluminum with a hard coat anodized black finish. Compatible With: G36 models SL8...HKP-01878$244.95 -
HKP HK MR556/416 Upper 8" 416C Style Conversion Kit
HKP HK Parts
$1,285.95MR556 & HK416 Upper Conversion Kit - 8" - HK 416C Style Finally an answer for all of those that have been wanting as close to the original, rare unicorn of a find HK 416C 8" barrel conversion kit for 416 or MR556. Each conversion kit upper or barrel...HKP-18629$1,285.95 -
On Sale
Picatinny Rail - HK G36 - HKP
HKP HK Parts
Now: $99.95Was: $179.95Picatinny Rail - HK G36 - HKP HK Lateral Picatinny rail Ambidextrous for carrying handle. Compatible With: G36 G36K G36C Specifications: Material: aluminumhkp-18726Now: $99.95Was: $179.95 -
On Sale
H&K (5.56/.223) & (7.62x51/.308) Contact Piece For Paddle Mag Release - USED - BLEMISHED
H&K Heckler & Koch
Now: $18.95Was: $29.95H&K (5.56/.223) & (7.62x51/.308) Contact Piece For Paddle Mag Release - USED - BLEMISHED USED. COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. German HK...HKP-00465-BNow: $18.95Was: $29.95 -
H&K 93/53/33 (5.56/.223) Rear Receiver Section
H&K Heckler & Koch
$79.95H&K 93/53/33 (5.56/.223) Rear Receiver Section Each rear receiver section is from a factory German HK 33/53 that was demilled and includes the welded on rear sight base and push pin bushing intact.HKP-16481$79.95 -
Out Of Stock
H&K G36/SL8 (5.56/.223) Single Optic Carrying Handle - Used
H&K Heckler & Koch
$0.00HK German G36, SL8 Single Optic Carrying Handle In Used Shape.HKP-00806$0.00 -
Out Of Stock
H&K HK 416A5 Stripped Upper Receiver - Black
H&K Heckler & Koch
$0.00HK 416A5 - Stripped Upper Receiver - Black 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...HKP-18786$0.00 -
Out Of Stock
H&K HK G36 Complete 1.5X Single Optic Carrying Handle
H&K Heckler & Koch
$0.00H&K HK G36 Complete 1.5X Single Optic Carrying Handle The 1.5X single optics are quite rare. Mounting hardware sold seperately.HKP-16742$0.00 -
Out Of Stock
H&K HK G36 Dual Optic With Carrying Handle - Used
H&K Heckler & Koch
$0.00HK G36, SL8 Dual Optic - Used PD trade in'sFactory HK G36/SL8 dual optic in used condition. This is a one time offering as far as we will not be able to get them again!Fits all: G36 G36K G36C Sl8-1, Sl8-4 & Sl8-6 models.HKP-00744$0.00 -
H&K HK G36 Picatinny Rail - Black
H&K Heckler & Koch
$195.99H&K HK G36 Picatinny Rail - Black HK Lateral Picatinny Rail - Ambidextrous for Sight Rails. Compatible With: G36 G36K G36C Specifications: Material: AluminumHKP-18725$195.99 -
On Sale
H&K HK MP5 Rear Receiver Section - BLEMISHED
H&K Heckler & Koch
Now: $19.95Was: $24.95H&K HK MP5 Rear Receiver Section - BLEMISHED DOES NOT INCLUDE SIGHT BASE. COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. HK German demilled receiver section...HKP-02147-BNow: $19.95Was: $24.95 -
Out Of Stock
H&K HK MR556/MR223 A5 Incomplete Upper Receiver - Black
H&K Heckler & Koch
$0.00HK German Un-Assembled/Stripped HK MR556/MR223 A5 Upper Receiver Factory HK MR556 A5 upper receiver. This is the semi-auto MR556 variant. Compatible With: HK MR556 HK MR223 HK 416*** Need a matching lower for your build? STS416 A5 LOWER -...HKP-18785$0.00 -
Out Of Stock
H&K HK UMP Demilled Extended Rear Receiver Section
H&K Heckler & Koch
$0.00HK German Factory UMPÂ Receiver Section - ExtendedThis is a demilled factory HK UMP rear receiver section that is perfect for the new Tom Bostic USC-UMP conversions. This section is the perfect length in order to do the USC/UMP conversion. Just in only...HKP-19798$0.00 -
On Sale
H&K HK416 A5 Factory German Extended Castle Nut - BLEMISHED
H&K Heckler & Koch
Now: $48.95Was: $71.95H&K HK416 A5 Factory German Extended Castle Nut - BLEMISHED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. Original HK Factory German steel 416 A5 Extended...HKP-19164-BNow: $48.95Was: $71.95 -
Out Of Stock
H&K HK416, MR556 Ejection Port Cover - FDE
H&K Heckler & Koch
$0.00HK German HK 416, MR556 Ejection Port Cover In RAL7008 -FDE HK manufactured newer polymer style cover assembly found on the latest HK 416 & MR556's. This item can also be used on other AR15 style projects to enhance the project with the finest...HKP-19450$0.00 -
Out Of Stock
H&K UMP (.40 S&W/.45 ACP/9mm) Demilled Rear Receiver Section
H&K Heckler & Koch
$0.00HK UMP Demilled Receiver Section This is a demilled factory HK UMP rear receiver section that is perfect for the new Tom Bostic USC-UMP conversions. This section is the perfect length in order to do the USC/UMP conversion. Last one available.HKP-01659$0.00 -
Out Of Stock
H&K UMP (.40 S&W/.45 ACP/9mm) Incomplete Pistol Grip (0,1)
H&K Heckler & Koch
$0.00UMP Pistol Grip Stripped & Incomplete - 2 Position (0,1) Pictogram New HK German manufacture, rare and hard to find. If you have an HK USC you can use this housing with the USC lower internals for a complete USC to UMP lower assembly that you can use...HKP-17815$0.00 -
HKP HK MP5 Receiver Flat - Smooth Top
HKP HK Parts
$125.95HKP HK MP5 Receiver Flat - Smooth Top The MP5 receiver flat has been meticulously crafted by the original German tool and die maker of the LSC receiver flat, utilizing factory original German prints and specifications. This receiver boasts a flat top,...HKP-21552$125.95 -
On Sale
HKP HK MP5K QD End Cap with Buffer - Black - BLEMISHED
HKP HK Parts
Now: $32.95Was: $44.95HKP HK MP5K QD End Cap with Buffer - Black - BLEMISHED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. Compatible With: MP5K SP89 Clone or other custom buildsHKP-20117-BNow: $32.95Was: $44.95 -
HKP HK MP5K Receiver Flat - Smooth Top
HKP HK Parts
$129.95HKP HK MP5K Receiver Flat - Smooth Top The MP5K receiver flat has been meticulously crafted by the original German tool and die maker of the LSC receiver flat, utilizing factory original German prints and specifications. This receiver boasts a flat top,...HKP-21550$129.95 -
Out Of Stock
HKP HK MR556/416 Upper 9" 416C Style Conversion Kit
HKP HK Parts
$899.95MR556 & HK416 Upper Conversion Kit - 9" - HK 416C Style Finally an answer for all of those that have been wanting as close to the original, rare unicorn of a find HK 416C 9" barrel conversion kit for 416 or MR556. Each conversion kit upper or barrel...HKP-18674$899.95 -
Out Of Stock
HKP Magazine Catch - Latest Style
HKP HK Parts
$19.95HKP Magazine Catch - Latest Style New, latest generation 1-piece 9mm mag catch. If you have issues with mags locking in place on clones or non-HK German firearms, it may be that you need this upgrade. One-piece constructiong versus the older generation...HKP-17571$19.95