If you own an MR556, you need the best HK MR556 upgrades and accessories to maximize the rifle’s effectiveness.
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These are high-tier battle rifles, and they come near perfect from the factory. You will still need to add some parts to complete the build.
This article will cover the best HK MR556 upgrades and accessories.
What Is A HK MR556?
Simply put, the MR556 is the civilian version of the HK 416. This is a pistol AR-15 that is chambered in 5.56 Nato.
These are premium and overbuilt rifles that function extremely well. They are known for being reliable and also expensive.
The biggest downside of these rifles is the weight. They are heavy and cumbersome.
Like the HK416 and M27, the MR556A1 uses a proprietary HK gas piston and pusher-rod operating system in place of the gas tube normally found in AR15/M16/M4-style rifles.
This closed system eliminates malfunctions common in direct-impingement gas systems since hot carbon fouling and waste gasses are not propelled into the upper receiver to operate the action.
MR556A1 barrels are unlined for superior accuracy while maintaining exemplary service life under semi-automatic fire.
The MR556A1 barrel has six lands and grooves and a 1 in 7” twist. It is a taper-bore configuration with a slightly smaller internal diameter at the muzzle than at the chamber end for improved accuracy and velocity.
Where To Purchase A HK MR556?
If you do not already own an HK MR556, your best chance is to find one online. Every gun store in my area has not had any of these in stock, but your location may differ.
Ordering one online and sending it to your local FFL is the easiest way to pick up one of these awesome guns. Here is a link to the HK MR556 if you want to order one.
Click Here to check the current prices and availability of the HK MR556
HK MR556 CURRENT MODELS IN PRODUCTION
- Click Here to view them on H&K’s website
- Click Here to download the owner’s manual
Best HK MR556 Upgrades & Accessories
These rifles are great out of the box and need little work to set them up right. The handguard is great, and the same with the rest of the furniture.
I normally swap out the butt stock on all of my AR-style rifles, but on this one, I like it. It is well made and very comfortable.
The primary accessories I recommend are an optic and a good weapon light. This is what you should focus on first.
Without further ado, these are the best HK MR556 upgrades and accessories.
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Best HK MR556 Optics
This very capable platform can be used in many different scenarios. I recommend using a red dot sight if you plan on using this primarily as a home defense gun.
If you want more of a “do it all” gun, then adding a low power variable optic (LPVO) is what I recommend. Regardless of what you decide, all of the optics I list are of great quality and will work great on the MR 556.
Choosing between them depends on personal preference and the intended purpose for which you want the HK MR556 to be used.
Also, don’t go cheap on an optic for this rifle. It deserves a premium optic.
Best HK MR556 Red Dot
If you want the fastest sighting option, then a red dot is the way. They are quick and allow you to threat focus/target focus instead of focusing on the front sight like you would on traditional iron sights.
If you want some magnification to be added to your red dot, then a magnifier is a great option and gives you the best of both worlds.
There are three primary red dots that I recommend.
- Aimpoint CompM5
- Aimpoint T2
- EOTech EXPS3
Aimpoint CompM5
The best red dot sight for the HK MR556 is the Aimpoint CompM5. This is the most durable and reliable red dot you can purchase.
These have a superior light transmission with 4 night vision and 6 daylight settings for better daytime and night accuracy. The 2 MOA red dot is powered by ACET technology for over 50,000 hours of constant operation.
Advanced optical lenses are held in a durable and lightweight housing, and the Aimpoint CompM5 ACET Red Dot Sight is keyed into the mount base to absorb recoil.
The quality is what you would expect from a top-tier optic company. This optic is all you need to finish any close-range setup. The AAA battery usage wins for much easier to replace batteries and easier to store.
It is light for its size but similar to optics its size. The reliability and battery life are the two biggest pros of the Aimpoint CompM5.
If you want a bomb-proof red dot, then this is what I recommend. The only downside of the CompM5 is the price. It is expensive, but you get what you pay for, especially in the firearms industry.
It’s sleek, solid, crystal clear, and has a much more versatile battery option than many other small red dot units. You can’t go wrong with the CompM5.
If you have been holding off on a high-end red dot, now might be the time to pick one up finally.
Click Here to check the current prices of the Aimpoint CompM5
Aimpoint T2
Designed to be the ideal sight for tactical applications, the Aimpoint T2 is one of the best compact red dots.
It is lightweight, extremely reliable, and has long battery life.
The sight housing of these red dots has advanced lens coatings that radically improve the shape and clarity of the 2MOA red dot.
Physical protection has been added around the adjustment turrets and internal changes to protect the electronic components of the T2.
The sealed tube design of this Aimpoint red dot means that snow, rain, dust, mud, or sand will not hinder the use of your sight or ever get in between you and your target.
The optic can be mounted quickly and has a clear, crisp dot in the center. Perfect for making accurate shots rapidly.
If you want one of the lightest red dot setups, then the T2 is what I recommend. It works great but in a compact package.
This red dot is compatible with all generations of night vision devices.
Click Here to check the current prices of the Aimpoint T2
EOTech EXPS3 with G33 Magnifier
The EOTech EXPS3 w/ G33 Magnifier is the close-quarter tactical accessory for incredibly fast target acquisition capabilities, true heads-up display design, and versatile reticle adaptability.
These give you a true heads-up display that eliminates blind spots, reduces tunnel vision, and improves peripheral performance, and the EXPS3 allows you to target with both eyes open.
The reticle of the EO-Tech EXPS3 Holographic 1x Scope stays consistently visible with thirty different brightness settings, including ten settings optimized for night vision devices. When you don’t want to use the red dot sight’s reticle, the 7mm raised base allows you to use your iron sights. 
While the EPXS3 is a potent weapon sight, its 1x magnification limits your weapon’s range to close quarters. The G33 Magnifier will boost the magnification rate of the EXPS3 by 3.25x.
If you have any vision problems or astigmatism, EOTech is the best choice for you. The parallax-free holographic design will give you the clearest image.
The Magnifier has a wide field of view, maintaining the fast target acquisition capabilities of the standalone holographic sight even at 3.25x magnification.
The magnifier is attached to a Quick Switch to Side (STS) mount, which allows you to quickly switch between 1x and 3.25x magnification by moving the magnifier to the side and back again.
Click Here to check the current prices of the EOTech EXPS3 w/ G33 Magnifier
Best HK MR556 LPVO
LPVO scopes are becoming very popular, and even the U.S. Army has started to issue them on their new rifles. They are a great option if you want a good rounds rifle that can engage targets to close but also reach out a little further.
They are still not as fast as a red dot at 1x but are still very quick. Remember that you will also need a good quality mount for a scope.
There are three LPVO scopes that I recommend for the HK MR556.
- Vortex Razor Gen II-E
- Sig Sauer Tango 6T
- NightForce NX8
Vortex Razor Gen II-E 1-6x24mm Rifle Scope
One of the best overall LPVO scopes and my go-to is the Vortex Razor Gen II-E. It has all of the features you want, is of great quality, and is reasonably priced.
The clarity, color accuracy, resolution, and eye relief are outstanding and are truly a high-end scope.
The Vortex Razor HD Gen II is an ultra-sleek design built like a tank. The Gen II-E is packed full of unique features and is overbuilt.
This scope is well thought out and has everything you need in an LPVO. It truly is a premium optic and works flawlessly.
The scope is designed on a single-piece tube that maximizes alignment for improved accuracy and optimum visual performance and ensures strength and waterproofness.
The second focal plane reticle scale maintains the same sized appearance. Listed reticle subtensions can be used for estimating range, holdover, and wind drift correction are accurate at the highest magnification.
Illuminated center dot daylight bright illuminated center dot provides a precise point-of-aim in all lighting conditions. The illuminated reticle provides precise aiming under low-light conditions.
If you want to learn more about this scope, I will link my Vortex Razor 1-6 Full Review.
Click Here to check the current prices of the Vortex Razor Gen II-E
Sig Sauer Tango 6T 1-6x24mm Rifle Scope
The Sig Sauer Tango 6T is an excellent optic for the HK MR556 and has been chosen to be mounted on the U.S. Army’s new rifles.
These are made with HDX optics extra-low dispersion glass paired with high transmittance glass to create the brightest and most vivid sight pictures for your shooting needs.
This Sig Sauer Tango 6T features night vision illuminated reticle settings so that you can use this optic alongside your night vision devices.
The illuminated reticle and fast focus eyepiece allow you to acquire targets quicker than ever, and the reticles are also glass-etched in case you run out of power.
All of the Sig Tango 6T scopes come with an integrated throw lever to quickly adjust the magnification on the fly.
The Hellfire reticle is great and is a good balance of information without making the reticle too busy.
Click Here to check the current prices of the Sig Sauer Tango 6T
Night Force NX8 1-8x24mm Rifle Scope
The Night Force NX8 is the perfect scope for short to mid-range missions that require superior optics with minimal weight and size. It is a 30mm tube with a 1-8x range for magnification.
This is a premium optic and one of the top LPVO scopes on the market.
These feature a revolutionary center dot visible in the daylight for rapid target acquisition and engagement, and the built-in power throw lever aids in fast magnification changes.
The Night Force NX8 1-8x24mm Illuminated Rifle Scope is built from top-quality materials and constructed with a 30mm body tube for superior strength and durability.
The glass clarity is out of this world and provides a bright, clear, and crisp image. The eyebox is the most generous I have seen from any other LPVO. When zooming in and out, the focus and image remain clear.
Mount this Night Force NX8 1-8x Rifle Scope on your HK MR556 for the best performance in the field.
Click Here to check the current prices of the Night Force NX8
Best HK MR556 Scope Mount
Once you decide on a scope, you will need a solid way to mount it on your HK MR556. Just make sure that you get the proper ring size. In most cases, it will be either a 30mm or 34mm tube size.
Geissele Super Precision Scope Mount
One of the best scope mounts I recommend is the Geissele Super Precision Scope Mount. This is my go-to mount for all my scopes and is the best on the market.
It will hold zero and stand up to the recoil of firing without any issues. These are very well-made and precise, so no lapping is needed for the rings.
These mounts are available in either 30mm or 34mm tube diameters and various lengths, including standard, extended and hyperextended. This allows you to get the perfect length for your chosen scope, ensuring it fits on your rifle easily.
While these scope mounts use the classic nut and bolt method for clamping to the Picatinny rail. This means they are more secure, as each nut and bolt combination provides 1,400 pounds of clamping force, which is more than any lever mounting arrangement.
It also spans 7 Picatinny sections and uses four shear lugs to ensure the scope stays steady and zeroed even after repeated firing.
Click Here to check the current prices of the Geissele Super Precision Scope Mount
Best HK MR556 Light
For any serious battle rifle or self-defense gun, you need a good weapon light. It needs to be reliable and bright.
There are many good options nowadays for weapon lights, but I always go back to the tried and true one.
SureFire M600 Ultra Scout Light
Identifying your target is crucial; if it’s dark, you will need a weapon light.
The Surefire M600 is my go-to for this. It is bright, reliable, and has the option to add a tape switch with a pressure pad for momentary on and off.
These have been around a while and are still trusted as one of the best weapon lights.
Click here to check the current prices of the Surefire M600
Tail Cap Pressure Pad
They make a Tail Cap Pressure Pad with a button, letting you have a constant on and off button.
With this switch, you can have the most efficient ergonomic light setup and will not have to move your hand to activate it. This will stop you from breaking your shooting grip.
Click here to check the current prices of the Tail Cap Pressure Pad
Arisaka Defense Inline Scout Mount
I mount this on my handguard using the Arisaka Defense Inline Scout Mount. It’s slim and rock solid.
It takes up minimal rail space and is MLOK, so you can easily attach the Surefire M600 to the HK MR556.
They also make this mount in Keymod as well.
Click here to check the current prices of the Arisaka Defense Inline Scout Mount
Cloud Defensive LCS Mount
I have the tape switch running to a Cloud Defensive LCS Mount that works great. I am super happy with this setup and believe it’s the best solution for mounting a weapon light with a pressure pad.
It is slim and has channels to route the cable under the mount. Again this is an M-LOK part but they make a Keymod version also.
Click here to check the current prices of the Cloud Defensive LCS Mount
Best HK MR556 Magazines
Having extra magazines is a must for any rifle. The good thing about the HK MR556 is that it takes standard AR-15 style mags as long as they are modern.
Some people feel better using the HK mags. They work great but are more expensive.
Magpul PMAG Gen 3 w/ Window
I like using the Magpul PMAGs Gen 3 with the window and never had any issues using these in the HK MR556.
These magazines are very consistent and fit into mag wells perfectly. They feed reliably and are fairly priced. (Even in today’s market)
I also like to stock up on PMAGs when I can.
Click here to check the current prices of the Magpul PMAGs Gen 3
Best HK MR556 Ammo
You will always need more ammo, and with prices at a high, the best idea is to better it whenever you see a sale or buy in bulk.
5.56mm is pretty common, so it’s normally easy to find.
Be sure to click the links and check the current prices and availability of the ammo because prices always change.
- 5.56mm
HK MR556 FAQ
How good is the MR556?
The HK MR556 is a premium AR platform rifle. It is reliable and incredibly smooth to shoot. The gas piston system increases the rifle’s reliability, especially when suppressed.
How much is the HK MR556?
These rifles are high-end options and usually run in the $3,500 price range, depending on where you order one from.
Is the MR556 piston driven?
The HK MR556 uses a proprietary piston gas operating system. This adds weight to the rifle but increases the reliability in adverse conditions.
Where is the MR556 made?
The MR556A1 is assembled in the USA using the US and German-made components and uses many of the same parts and assemblies developed for the HK416.
Complete List of Items Mentioned
(Click the links for the most up-to-date prices)
- HK MR556
- Aimpoint CompM5
- Aimpoint T2
- EOTech EXPS3 w/ G33 Magnifier
- Vortex Razor Gen II-E
- Sig Sauer Tango 6T
- Night Force NX8
- Geissele Super Precision Scope Mount
- Surefire M600
- Tail Cap Pressure Pad
- Arisaka Defense Inline Scout Mount
- Magpul PMAGs Gen 3
- 5.56mm
Have you added any accessories to the HK MR556?
Did you initially start with an optic?
Let me know in the comments below.
Further reading on Firstworldcrusader.com: Are you interested in learning more about guns and gear?
This list of the Best Red Dot Sights can help you choose the best optic for your rifle.
In addition, here are the Best AR-15 Upgrades & Accessories that can help you get more out of your primary battle rifle.
