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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HKP MP5 Replacement Buffer for Folding Stock or End Cap
HKP HK Parts
$3.49HKP MP5 Replacement Buffer for Folding Stock or End Cap Spare replacement buffer for choate folding stocks or end caps. Compatible With: Choate MP5 and MP5K stocks or end capsHKP-18735$3.49 -
Out Of Stock
B&T MP5, MP5K - Low Profile Scope Mount
B&T Brugger & Thomet
$119.95B&T MP5, MP5K - Low Profile Scope Mount B&T low profile scope mount, Compatible With: HK MP5 SP5 MP5K SP5K Specifications: Color: Black Height max: 30.7 mm Length max: 84 mm Length of top rail: 84 mm Material: Aluminum NATO Accessory Rails:...HKP-16875$119.95 -
Choate MP5 & HK94 End Cap & Sling Swivel
Choate
$36.95Choate MP5 & HK94 End Cap and Sling Swivel 100% US-made MP5 and HK94 end cap features an extra thick heavy-duty rubber buffer that is replaceable with a simple screwdriver. Each HK end cap also features a sling swivel for use with all types of slings...HKP-00115$36.95 -
Out Of Stock
Semi Auto Shelf For Receiver - Billeted
$19.95Semi Auto Shelf For Receiver - Billeted HK Semi Auto Shelf milled from one solid billet to HK's factory specifications (no castings here). This is the needed receiver shelf that is welded to the receiver to allow the use of the clipped & pinned...HKP-01521$19.95 -
PTR HK 91/G3 (7.62x51/.308) Receiver Flat
PTR
$99.95HK G3, 91, PTR & CETME Flat - PTR Made by PTR with original HK tooling using factory specifications and a properly stamped receiver. No FFL is required as this is an unfolded flat that ships directly to the customer. This US made receiver flat...HKP-02320$99.95 -
HKP HK MP5 .22 Sling Clip Kit - Black
HKP HK Parts
$24.95HKP HK MP5 .22 Sling Clip Kit - Black Each unit will fit all models of the MP5 .22 that have the 3 mounting holes on the left side of the magwell. This item installs in a few mins and comes complete with all you need for the install. With the addition of...HKP-15706$24.95 -
B&T MP5, MP5K Low Mount For T1/H1 & T2 Aimpoint
B&T Brugger & Thomet
$99.95B&T MP5, MP5K Low Mount For T1/H1 & T2 Aimpoint Ideal for use with the Aimpoint line of T-1/T2 & H-1/H2 type of optics. This mount is the lowest low profile mount available for use with the T1/T2 style of mounting system. This same mounting...HKP-16862$99.95 -
PTR HK 91/G3/51 (7.62x51/.308) Flat With Weldment Set
PTR
$166.95HK91, G3, PTR, CETME Flat & Weldment Combo - PTR Made by PTR91 on original HK tooling using factory specifications and a properly stamped receiver ready to roll and build. No FFL is required as this is an unfolded flat. Compatible With: HK G3...HKP-02086$166.95 -
Out Of Stock
B&T MP5, MP5K Low Profile Mount, Extended T1/T2
B&T Brugger & Thomet
$159.95B&T MP5, MP5K Low Profile Mount, Extended T1/T2 Compatible With: Aimpoint T1/H1 & T/1/T2 style red dots such as the Vortex Viper, etc Specifications: Color: Black Height max: 23.5 mm Length max: 138 mm Length of top rail: 138 mm Material:...HKP-16876$159.95 -
HKP HK UMP/USC (.40 S&W/.45 ACP/9mm) 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 -
HKP Spare Buffer For Folding Stocks & End Caps
HKP HK Parts
$9.95HKP Spare Buffer For Folding Stocks & End Caps New US manufactured flat style "H"buffer to replace the factory HK buffer on MP5K folding stocks and end caps. As well as a spare or replacement buffer for the MP5 & MP5K folding B&T stocks. Made...HKP-17886$9.95 -
HKP Flat Bending Billeted Jig Set For All HK Style Flats
HKP HK Parts
$449.95HKP Flat Bending Billeted Jig Set For All HK Style Flats NEW LATEST 4th GENERATION VERSION AND DESIGN. THE FINEST JIG SET AVAILABLE! Billeted universal flat bending jig for all HK receiver flats including our new PTR .308 flats and the...HKP-19583$449.95 -
HKP MP5/HK94 Complete Weldment Set For Receiver Flat
HKP HK Parts
$49.95HKP 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$49.95 -
Out Of Stock
HKP HK MP5 9mm Receiver Flat with Weldment Set
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 -
LSC MP5 9mm Receiver Flat
LSC
$199.95MP5 Receiver Flat - LSC LSC HK MP5 receiver flat is the most in spec flat that has ever been available. The best option for your HK German parts kit build. This flat is considered by many to be most sought after HK flat available on the market and...HKP-20555$199.95 -
PTR HK MP5 Flat Receiver w/ 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 -
Choate MP5 Replacement Buffer For Folding Stock Or End Cap
Choate
$3.95Choate MP5 Replacement Buffer For Folding Stock Or End Cap Compatible With: Choate MP5 and MP5K stocks or end capsHKP-00116$3.95 -
H&K HK MR556/MR762/416//417 Complete Piston Rod Assembly
H&K Heckler & Koch
$64.95H&K HK MR556, MR762, 416, & 417 Complete Piston Rod Assembly A great replacement or spare to keep on hand. Compatible With: HK MR556 HK 416 HK 416 A5 MR762 HK 417 Please Note: Does not fit barrels less than 10 inches.HKP-00042$64.95 -
Out Of Stock
HKP Semi Auto Shelf, Hanger Block For Receiver
HKP HK Parts
$13.95HK Semi Auto Shelf Weldment, Hanger Block Weldment HK Semi Auto Shelf, Hanger Block to HK's factory specifications for c/p trigger housings. Weld on shelf that is the needed receiver block that welds to the rearward portion of the magwell to allow the...HKP-17572$13.95 -
H&K Magazine Catch - MP5, MP5K - Latest Style
H&K Heckler & Koch
$64.95H&K Magazine Catch - Latest Style Genuine HK mag release for factory and clone firearms. This component often resolves issues with mags not locking into position on HK clones and builds. Constructed from a single piece of steel unlike the...HKP-00911$64.95 -
H&K HK MR556 Rear Lower Receiver Locking Pin
H&K Heckler & Koch
$79.95HK MR556, MR762 Locking Pin With Spring Loaded Detent This is the rear takedown pin with ball detent and locking mechanism installed. The idea behind this type of system is to decrease the movement of the upper and lower receivers and improve the...HKP-02672$79.95 -
HKP SP5K 9mm Drop In Paddle Mag Release Upgrade Kit
HKP HK Parts
$74.95HK SP5K Anti-Rattle Roller Tipped "Paddle" Magazine Release Install Kit No modifications, no refinishing...complete drop-in kit included. New USA made busing for a drop-in install kit for the HK SP5K. This kit will allow any end-user to quickly,...HKP-18192$74.95 -
Flat Bending Jig Set For All HK Style Flats - Billeted - All Steel
$599.95Flat Bending Jig Set For All HK Style Flats - Billeted - All Steel NEW- LATEST 4th GENERATION 100% ALL STEEL VERSION AND DESIGN. THE FINEST JIG SET AVAILABLE! All steel billeted universal flat bending jig for all HK receiver flats including our new...HKP-19595$599.95 -
LSC/PTR Receiver Flat- MP5 9mm
LSC
$239.95MP5 Receiver Flat - PTR/LSC New PTR 9mm Receiver Flat made on the original LSC tooling. This flat is considered by many to be the most sought-after HK flat available on the market and perfect for that HK custom build. This item is not considered an FFL...HKP-01431$239.95 -
H&K MP5K/SP89/SP5K 9mm End Cap
H&K Heckler & Koch
$99.95HK Factory German MP5K, SP-89, & SP5K End Cap With Sling Swivel Each pistol end cap is OEM HK German MP5K and MP5K-N and has the HK German factory buffer. Compatible With: MP5K SP89 SP5K MP5K-N MP5K-PDW MP5K Clone Or Other Custom BuildsHKP-00394$99.95 -
Chaote HK MP5K QD End Cap with Buffer - Black
Choate
$44.95Quick Detach MP5K, SP-89 Steel End Cap With Replaceable Rubber Buffer Compatible With: MP5K SP89 Clone or other custom buildsHKP-20117$44.95 -
HKP MP5 End Cap with Sling Swivel
HKP HK Parts
$84.95HK Alloy Pistol End Cap with Sling Swivel Made from solid billet aircraft grade aluminum with the HK German sling loop and rubber heavy duty H buffer. With the alloy construction this unit will not break like the plastic end caps. Compatible...HKP-18138$84.95 -
H&K HK MR556/416 Receiver End Plate
H&K Heckler & Koch
$24.95HK 416, MR556 End Plate For Receiver & Buffer Tube New HK German manufacture. Compatible With: HK MR556 & HK 416 upper receiever/buffer tubesHKP-16603$24.95 -
Choate HK MP5 QD End Cap with Buffer - Black
Choate
$99.95Quick Detach Steel End Cap With Replaceable Rubber Buffer - HK MP5 With this MP5 QD end cap upgrade you will get a heavier buffer to internally protect your firearm and keep your bolt carrier in tip top condition for years to come. Machined aircraft...HKP-20118$99.95 -
Tac Latch - PTR Spec
$69.95Tac Latch (latest Generation) PTR Spec - PTR .308 Firearms The new updated style of Tac latch is made specifically for the PTR 91 .308 receiver and will require very little modification to the firearm for installation. A major overhaul of the existing...HKP-17611$69.95 -
H&K HK MR556/MR762 Receiver Take Down Tool
H&K Heckler & Koch
$19.95HK MR556 & MR762 Take Down Tool For The Upper & Lower Receiver This part is the tool used to tighten down the stock movement on the E1/E2 stock. Each tool will be stored in the rear of the E1/E2 stock. Please Note: We get...HKP-02653$19.95 -
HKP MP5K/SP89/SP5K 9mm End Cap - HK Style
HKP HK Parts
$64.95HKP MP5K/SP89/SP5K 9mm End Cap - HK Style This end cap is an identical reproduction of the factory end cap and features the original HK style buffer. Compatible With: MP5K SP5K SP89 In spec. clones and custom buildsHKP-16135$64.95 -
H&K HK G36 Backplate w/ Recoil Buffer
H&K Heckler & Koch
$79.95HK G36 Backplate With Recoil Buffer This is a great spare or replacement to have on hand. These are also required for those that are doing the SL8-G36 conversions provided by Tommy Bostic & Chopstix Kid.HKP-01058$79.95 -
H&K HK MR556/MR762 Front Lower Receiver Locking Pin
H&K Heckler & Koch
$59.95HK MR556 Locking Pin With Spring Loaded Detent This part is the front (large) takedown pin with ball detent and locking mechanism installed. The idea behind this type of system is to decrease the movement of the upper and lower receivers and improve...HKP-02663$59.95 -
Choate MP5K/SP89 9mm Steel End Cap W/ Buffer
Choate
$45.95MP5K & SP-89 Steel End Cap With Replaceable Rubber Buffer Fits perfectly on all HK MP5K-type builds or projects. All metal construction, so you know it will last. Each unit comes with a sling loop for use with multiple sling types. Compatible...HKP-00395$45.95 -
H&K G36/SL8 (5.56/.223) Sight Rail With Front & Rear Sights
H&K Heckler & Koch
$289.95H&K German G36 & SL8 Picatinny Sight Rail With Front And Rear Iron Sights Each rail works well with optics such as Eotech or Aimpoints. This is also a great part if you want a lower cheek weld and low-profile sight system. Made from durable...HKP-00274$289.95 -
H&K HK SL8, HK G36 Extended Bottom Rail Kit - Black
H&K Heckler & Koch
$99.95H&K HK SL8, HK G36 Extended Bottom Rail Kit - Black This rail is the factory correct HK German manufactured bottom rail for the G36 or SL8 rifle. This allows the longest rail on the bottom of the polymer forearm. 9.25" in length overall. Comes with...HKP-16549$99.95 -
Out Of Stock
B&T MP5, SP5, 94, K - Mid Range Scope Mount
B&T Brugger & Thomet
$119.95B&T MP5, SP5, 94 - Mid Range Scope Mount Includes a witness hole so you can use iron sights with the mount installed. B&T Switzerland is a world leader in arms innovation. This same mount is in use by several militaries around the world. Buy with...HKP-16877$119.95 -
H&K HK MR556/416 Vented Slimeline Gas Block
H&K Heckler & Koch
$135.00HK German MR556, 416 Gas Block Complete - Low Profile This part is the factory slim-line, low-profile gas block for the MR556/HK416. There are no bayo lug or sling attachment points. This is the factory-correct gas block found on the...HKP-02660$135.00 -
Sale
HKP MP5K/SP89/SP5K 9mm Receiver Flat
HKP HK Parts
Now: $99.95Was: $159.95HK U.S Made MP5K, SP5K, & SP89 Receiver Flat HK MP5K receiver flat (no FFL required) as these are flats and are not considered receivers until the flat is rolled. These are the latest generation flats that have all of the latest improvements. Just...HKP-00768Now: $99.95Was: $159.95