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 MR556, MR223 Upper Receiver - BLEMISHED
H&K Heckler & Koch
$695.95HK MR556, MR223 Upper Receiver - BLEMISHED ONLY 1 UNIT AVAILABLE - AS PICTURED MISSING FORWARD ASSIST AND GAS PISTON COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE...HKP-16950-BL-B$695.95 -
On Sale
AR15 Buffer Tube - Hex - 7.5" - BLEMISHED
Sig Sauer
Now: $19.95Was: $44.95SIG Sauer Phase 5 Hex Buffer Tube for AR-15 Pistols - BLEMISHED ONLY 1 UNIT AVAILABLE - AS PICTURED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. This buffer...HKP-99304Now: $19.95Was: $44.95 -
HK416, MR556 Enhanced Buffer Tube - Tan
H&K Heckler & Koch
$192.95Tan HK 416, MR556 OTB (over the beach) Buffer Tube, Receiver Extension - Commercial Genuine HK German-manufactured 416 & MR556 latest generation, marine environment & and over-the-beach buffer tube. Each commercial buffer tube features built-in...HKP-22086$192.95 -
HK21E, HK23E Left Receiver Reinforcement Rail Weldment
H&K Heckler & Koch
$14.95H&K 21E/23E Left Receiver Reinforcement Rail Weldment Genuine German-made weldment for left-side receiver reinforcement rail. Precision-machined using the correct steel and milling for you HK21E or HK23E build. Compatible With: HK21E HK23EHKP-21907$14.95 -
HK MP5 Receiver Flat - 9mm - no Sling Clip
HKP HK Parts
$189.95HKP HK MP5 9mm Receiver Flat w/o Sling Clip The MP5 9mm receiver flat serves as the foundation for custom MP5 builds. This version does not include a sling clip cutout, offering flexibility for customization. Precision-engineered for compatibility with...HKP-21828$189.95 -
Out Of Stock
HK33, HK53, HK93 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 StockOn Sale
HK416, MR556 Takedown Pin - Front - A4 Style - BLEMISHED
H&K Heckler & Koch
Now: $15.95Was: $26.95HK416, MR556 Takedown Pin - Front - A4 Style - BLEMISHED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. The HK416 front takedown pin is a German-made component...HKP-21862-BNow: $15.95Was: $26.95 -
On Sale
HK VP9, VP40 Enhanced Magazine Release - Red- BLEMISHED
HKP HK Parts
Now: $36.95Was: $49.95HK VP9, VP40 Enhanced Magazine Release - Red- BLEMISHED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. The oversized magazine release increases the overall...HKP-21099-RE-BNow: $36.95Was: $49.95 -
On Sale
HK91, G3 Mag Release Set - USED
H&K Heckler & Koch
Now: $19.95Was: $34.95HK91, G3 Mag Release Set - USED ONLY 1 UNIT AVAILABLE - AS PICTURED USED PARTS ARE SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL USED PART SALES ARE FINAL. This magazine catch set consists of 4 pieces and is HK-manufactured. Includes: Magazine...HKP-00929-USEDNow: $19.95Was: $34.95 -
On Sale
HK UMP Paddle Mag Release - Extended - BLEMISHED
HKP HK Parts
Now: $24.95Was: $34.95HK UMP Paddle Mag Release - Extended - 9mm / .40 S&W / .45 ACP - BLEMISHED COSMETICALLY BLEMISHED PARTS ARE FULLY FUNCTIONAL AND SOLD AS IS. THIS PART IS NOT ELIGIBLE FOR RETURN. ALL BLEMISHED PART SALES ARE FINAL. Billeted alloy UMP magazine release...HKP-17919-BNow: $24.95Was: $34.95 -
HK91, G3, HK93 Anti-Rattle Mag Release
MKE
$32.95MKE Anti Rattle Paddle Magazine Release Upgrade your rifle with MKE's anti-rattle style paddle mag release. Compatible With: HK G3, HK91 HK33, HK53, HK93 HK PSG1, MSG90 In-spec clones and custom buildsHKP-99348$32.95 -
HK417, MR762 Upper Receiver and Handguard - Flecktarn
H&K Heckler & Koch
$1,489.95HK417, MR762 Upper Receiver and 13.5" Handguard - Flecktarn Factory HK MR762 matching flecktarn upper receiver and 13.5" handguard. ONLY 3 SETS AVAILABLE AND WILL NOT BE RESTOCKED Compatible With: HK MR762 HK417HKP-99325$1,489.95