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.
- Product
- Qty in Cart
- Quantity
- Price
- Subtotal
-
HK MP5 Trunnion - .40 S&W, 10mm
HKP HK Parts
$139.95MP5 40 & MP5 10mm Trunnion Machined from ordnance-grade steel and heat-treated to factory specs. Each has the bullet guides pre-installed and included. These are the best USA-made trunnions on the market. Machined to HK spec, making the installation...HKP-02737$139.95 -
Out Of Stock
HK416, MR556 Magazine Catch - Ambi
H&K Heckler & Koch
$92.95H&K HK MR556, HK416 Mag Catch - Ambi Factory HK ambidextrous magazine catch/release. Compatible With: HK416 A5 HK MR556 A4 NOT compatible with earlier variants with single-side controlsHKP-22289$92.95 -
HK416, MR556 Takedown Pin - Front - A4 Style
H&K Heckler & Koch
$26.95H&K HK416, MR556 A4 Front Takedown Pin The HK416 front takedown pin is a German-made component designed to securely fasten the upper and lower receivers. Precision-machined for a proper fit, it ensures reliable function and serves as an ideal...HKP-21862$26.95 -
HK MP5K, SP89 Flat Receiver - 9mm
HKP HK Parts
$199.95MP5K, SP89 Receiver Flat - 9mm New MP5K receiver flat made by the original German tool and die maker of the LSC receiver flat utilizing factory original German prints and specifications. The creator of our receiver flat has been regarded as the premier...HKP-20733$199.95 -
HKP Front Sight Tower Ambi Sling Attachment Weldment
HKP HK Parts
$14.95HKP Front Sight Tower Ambi Sling Attachment Weldment Ambi sling loop that is welled and installed on all MP5F model front sight tower. A great upgrade for that custom build or for those that want to have the ability to have an ambidextrous sling loop at...HKP-17881$14.95 -
HK416, MR556 Buffer Tube - Enhanced - Commercial
H&K Heckler & Koch
$249.95HK 416, MR556 OTB (over the beach) Buffer Tube, Receiver Extension - Commercial: Genuine HK German manufactured 416, MR556 new style latest generation marine environment & over the beach buffer tube. Each Commercial buffer tube has built in drainage...HKP-15424$249.95 -
On Sale
AR-15 Commercial Buffer Tube
HKP HK Parts
Now: $16.95Was: $24.95AR-15 Commercial Buffer Tube Compatible With: All AR-15 style platforms Not correct length for HK rifles Features: Made From T7 7075 Aircraft grade aluminum Made in the USA 6 Position Each features a highly polished inside tube Black Mil-spec triple...HKP-02728Now: $16.95Was: $24.95 -
HK416, MR556 Charging Handle Roll Pin
$7.95HK 416, MR556 Roll Pin for Charging Handle - HKP This is the shorter one that is used on the inside of the charging handle. There are two of these pins used per charging handle.HKP-16536$7.95 -
Out Of Stock
HK416C Upper Receiver Kit - 9"
HKP HK Parts
$2,799.95HK416C Complete Upper Kit - 9" Our complete 416C upper kit includes everything you need to pair with a mil-spec lower or an STS 416C lower. For that genuine look, the STS 416C lower with the correct 416C stock eyelets is as good as you can get...HKP-21042$2,799.95 -
$24.99 -
HK G36, SL8 Cocking Handle Spring - US
USA
$9.95G36 Cocking Handle Spring- US Made Compatible With: G36 All variants SL8 All variantsHKP-18369$9.95 -
Out Of Stock
HK417, MR762, G28 Magazine Release - Ambidextrous
KDG Kinetic Development Group
$169.95Magazine Release - Ambi - HK MR762, 417, G28 The HK 762 Ambi (Ambidextrous) Magazine Release. This is the first ambidextrous magazine release for the HK 417 variant rifles. The mag release is a lever instead of a button; where the release has been...HKP-19204$169.95