Due to applicable state laws and regulations, we will not ship Forced Reset Triggers (FRTs) to the following locations: CA, CO, CT, DE, HI, IL, MA, MD, NJ, NY, OR, RI, WA, and DC. Orders placed with a shipping address in any of these states will be canceled and refunded.
FRT-MR3™ (FLAT)
Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556
NOTE: Max of two triggers per transaction.
Contents:
- 1 x FRT-MR3 Trigger
- 2 x Anti-Walk Pins
- 4 x Anti-Walk Pin Screws
- 1 x A1 Selector Drum
- 1 x A4 Selector Drum
- 2 x Selector Lever Roll Pins
- 2 x T10 Torx Wrenches
$525.00
In stock
FRT-MR3™ (FLAT)
Single-Stage (3-Position) Forced Reset Trigger for the HK MR223 & HK MR556
Take your HK MR223 and HK MR556 to the next level with the official Rare Breed Triggers FRT-MR3™ (FLAT). This drop-in, duty-grade 3-position Forced Reset Trigger (Safe/Semi/FRT®) is 100% manufactured and assembled in the USA. The FRT-MR3™ (FLAT) includes 3-position ambidextrous A1 (0/90/180) and A4 (0/45/90) safety bodies and anti-walk pins for a secure, hassle-free installation.
Performance on the Range
Enhance your shooting experience with the FRT-MR3™ (FLAT) Forced Reset Trigger. Designed to accelerate follow-up shots while remaining within legal parameters, the innovative Forced Reset system resets the trigger after each shot, enabling faster, more consistent firing. Each trigger pull fires one round, ensuring full legal compliance while delivering improved speed and performance. Perfect for competitive shooting, tactical training, or maximizing your HK MR223 and HK MR556’s potential.
Innovative Design and Features
- 3-Position Functionality: The FRT-MR3™ (FLAT) features Safe, Semi, and Forced Reset modes, controlled via a 3-position, ambidextrous safety selector. Whether you’re focused on precision shooting or rapid-fire drills, this system adapts to your needs, offering versatility for both left- and right-handed shooters.
- Effortless Installation: Designed for easy installation on HK MR223 and MR556 lowers, the FRT-MR3™ (FLAT) includes anti-walk trigger pins, providing secure attachment and preventing unwanted movement during extended use. The A1 (0/90/180) and A4 (0/45/90) safety bodies seamlessly integrate into HK MR223 and MR556 lower receivers while reusing the stock levers.
Durable Construction for Long-Lasting Performance
Crafted from high-quality materials, including 7075 anodized aluminum and heat-treated 4140 and S7 steel, the FRT-MR3™ (FLAT) is built to endure heavy use. This robust construction ensures reliability and longevity, allowing you to push your HK to its limits with confidence.
Compatibility with the HK MR223 and HK MR556
The FRT-MR3™ (FLAT) is specifically engineered to operate with the factory semi-automatic bolt carrier group (BCG) used in the HK MR223 and HK MR556 platforms. For that reason, the FRT-MR3™ (FLAT) is compatible with the HK MR223 and MR556 uppers when used with the original, factory-supplied semi-auto BCG. For optimal performance and reliability, we recommend retaining the factory buffer and recoil spring. Please note: The FRT-MR3™ (FLAT) is not compatible with HK416 or BRN4 full-auto bolt carrier groups.
Unmatched Speed and Control
The FRT-MR3™ (FLAT) is ideal for shooters seeking speed and precision. By mechanically resetting the trigger after each shot, then locking the trigger from being pulled until the BCG returns to battery, this system allows for faster follow-up shots without needing advanced techniques. The forced reset mechanism ensures the trigger returns to the non-firing position after each round, requiring the shooter to pull the trigger again, offering full control over each shot.
Why Choose the FRT-MR3™ (FLAT) Forced Reset Trigger?
If you’re looking to boost your HK MR223 and HK MR556’s performance, the FRT-MR3™ (FLAT) Forced Reset Trigger is the ultimate upgrade. With its rapid-fire capability, secure anti-rotation design, and seamless compatibility with the HK MR223 and HK MR556 platforms, this trigger provides a superior shooting experience for competition, tactical use, or range drills. Unlock the full potential of your HK MR223 and HK MR556 with the FRT-MR3™ (FLAT).
Manufactured and Assembled in the USA
Patent Notice: This product is covered by one or more U.S. Patents, including U.S. Patent Nos. 10,514,223; 11,724,003; 12,036,336; 12,274,807; and 12,636,403. Additional patents may be pending. Unauthorized manufacture, use, sale, or importation of this product or its covered features may constitute patent infringement.
As always, Rare Breed Triggers encourages the safe and responsible use of our products.
| Weight | 5 oz |
|---|---|
| Dimensions | 1 × 1 × 1 in |
27 reviews for FRT-MR3™ (FLAT)
Add a review
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TJ –
I was sitting on the fence for a couple months before deciding the jump. Turns out, the MR3 is an excellent upgrade for the MR556. I was a bit town between the curved and flat trigger shoe option. I ended up going with the flat version. The flat shoe gives the trigger a precise, intentional feel, and the quality of the MR3 is immediately apparent. Most importantly, the MR3 doesn’t sacrifice a good semi-auto trigger to deliver its forced-reset capability. Rare Breed managed to give the MR556 more capability without making it feel like less of an HK. In fact, it’s an obvious step up by allowing the HK to live like it was born to.
B_Law –
I went back and forth between the curved and flat versions before finally ordering the flat. No regrets. It feels very natural in my MR556 and I actually really appreciate the flat trigger when shooting in normal semi.
Of course, nobody spends MR3 money for semi. I was thinking that the third position was the price of admission but I have gotta say, I was only expecting semi to be decent or good. I was surprised to realize just how nice the trigger pull in standard semi really is. Rare Breed built an extremely nice trigger all around. Semi is extremely nice, arguably better than anything else out there and of course, they also provide the fun switch. This trigger is worth every single dollar and my rifle has become very expensive to feed.
Shane –
I went with the flat version of the MR3 and have been very happy with it. The straight trigger face feels comfortable and gives the rifle a slightly more modern feel. Semi-auto is smooth and predictable, and the overall quality is excellent. But that third position is obviously the fun part, but the flat trigger shoe of the MR3 is most noticeable when in standard semi and the pull feels like glass!
TJ –
The MR3 gets two thumbs up from me. The flat trigger shoe has such a comfortable face, nice semi pull, and a clear reset. Rare Breed, I like what you did with this one!
Jesse –
I bought an MR556 because I wanted German engineering. I bought the flat variant of the MR3 because apparently German engineering needed a little Texas flare. The flat trigger feels fantastic, the rifle is still an absolute pleasure to shoot in semi, and that third selector position changes the conversation entirely. Everything about the MR3 feels high-quality and built for hard use. Fair warning: bring more ammo than you think you need. Then bring another case cuz this FRT eats like a teenage boy.
Luke –
MR556 + MR3 Flat = problem solved. The flat blade feels fantastic, semi is a serious upgrade, and the third position is pure trouble in the best possible way. HK brought the engineering. Rare Breed brought the attitude.
Dean –
The flat variant of the MR3 is one of the rare upgrades that genuinely changes the character of the MR556 without taking anything away from what makes the rifle so good. The flat shoe provides a defined and repeatable contact point, and the trigger has a purposeful mechanical feel that complements the HK operating system exceptionally well.
What impressed me most is the overall execution. The forced-reset function may be the headline feature, but the quality of the trigger in ordinary semi-auto is what convinced me this was money well spent. Rare Breed engineered a complete trigger system here, not a one-trick pony and oh boy does it show!
Austin –
Fantastic trigger for the HK MR556. The flat blade feels great, semi is a major improvement over factory, and FRT mode delivers exactly what I hoped for; straight fire!
WG –
I chose to go with RB’s flat version of the MR3 because I’ve always preferred a straight trigger, and this one did not disappoint. The flat trigger blade gives the trigger a very deliberate feel and just feels good in the rifle. Semi is so nice and predictable, the controls feel substantial, and the entire unit has a high-quality feel that you notice immediately. This allows for extremely precise shot placement. Then there’s the third position. That’s where the responsible range session tends to lose the argument. But also, in the HK, this trigger just eats. Rare Breed absolutely nailed this one.
Big_Charlie_B –
I was curious how the flat version would compare with the curved trigger. The straight shoe feels natural and It’s growing on me more and more by the day. I’ve run more than 2500 rounds through it now and the trigger runs so well. I was also a little skeptical about FRT’s in general when I purchased this one but I have a new found confidence in the Rare Breed FRT’s. These guys put out a seriously hard core product. No BS. This thing just runs. Semi-auto is smooth with a clean break and forced reset mode is wild. It has earned a permanent spot in this rifle.
Mason R –
I have always preferred flat triggers, so this was the version I wanted to try. It was easy to throw into my HK MR556. The RB MR3 feels like it should have come with the rifle. It feels solid and mechanical sound. The trigger is a clear upgrade to the OEM. This thing is solid and I am happy with my choice.
Tate –
I was mainly looking for a cleaner trigger without changing the feel of the platform. The flat version of the MR3 feels properly matched with my HK MR556. Nothing about the fit feels improvised. I’ve spent approx 400 rounds now. Not that the pull and reset weren’t amazing right out of the package but I definitely feel comfortable saying they have improved a bit after the first few mags. This FRT is no gimmick. It is so well built that it has earned a permanent spot in the build.
Ethan –
I installed and have the trigger running in an MR556. The straight shoe feels natural and I’m a big fan. The semi-auto mode is better than the trigger that came with the rifle. And, FRT mode is straight fire. I love this fine piece of machinery! Thank you Rare Breed!
Cody H –
This is the second Rare Breed trigger I have purchased and both have been outstanding. The flat version of the FRT-MR3 is exactly what the HK platform deserved. The flat trigger blade provides an excellent consistent press point. Semi-auto feel is superb and FRT mode on the MR556 is incredible. It is so smooth, fast, and controllable. Installation took about 15 minutes with no issues. Rare Breed keeps earning my loyalty and my business.
Dustin H –
This is my first Rare Breed product and it absolutely will not be my last. The FRT-MR3 installed perfectly in my MR223 and the flat trigger blade feels incredibly natural. The rifle runs fast and smooth in FRT mode. And the standard semi-auto mode is so much better than the factory trigger. If you have an MR223, this trigger is for you!
James –
This trigger is badass and the flat blade version is even better than I expected. The MR platform deserved an aftermarket trigger this good and Rare Breed absolutely delivered. After running it through 400 rounds I am completely sold. Runs ridiculously well in forced reset mode and the quality of the standard semi-auto mode is top notch. Well done guys!
Marcus –
Running the FRT-MR3 Flat in my MR556 A3 alongside a Trijicon ACOG. The flat trigger blade is the right tool for this platform — ergonomic consistent and precise. Semi mode is clean and predictable. FRT mode on a piston gun with a quality optic is an experience that makes you rethink what a rifle can do. The gun just sits flat and eats! Rare Breed every single time.
Derek –
Switched from the curved MR3 to the flat version after shooting a buddy’s flat-trigger AR build. The flat blade makes a real difference in how consistently I press the trigger — especially during fast strings of fire where perfect finger placement is difficult. The flat version just feels great.
Nate –
The FRT-MR3 Flat is an outstanding trigger. The flat shoe gives you a more natural press angle and very consistent pull weight across the entire trigger travel. Semi-auto break is clean every time. FRT mode is wild. Running it in my MR556 and it runs perfectly suppressed and unsuppressed. Rare Breed is the only name I trust!
Levi T –
Flat trigger shooter through and through. Never considered a curved trigger in any of my builds. So when Rare Breed dropped the flat version of the MR3 I ordered within minutes. It did not disappoint. The flat shoe on the MR platform feels completely natural and the consistency of the press is exceptional. The trigger pull in semi-auto is so freaking nice. It’s better than the OEM by a long shot. FRT mode in this platform is smooth in a way that impresses even people who have shot a lot of AR FRTs. This rifle and trigger are an amazing pair!
Cody F –
My brother and I both own an MR556. He already has the curved FRT-MR3 in his rifle so I decided to try the flat version. I am not completely sold on the flat being better than the curved. I really love the curved trigger blade and I like the flat one too. I’m not sure which way I’m leaning in that regard. That said, the trigger itself is straight awesomeness. While the jury is still out on the curved vs straight, I def could not be any happier with the trigger. It is amazing!
Cody –
This is the second Rare Breed trigger I have purchased and both have been outstanding. The flat trigger blade of the FRT-MR3 is exactly what I wanted. It provides an excellent, consistent press point. Semi-auto feel is superb and FRT mode on the MR556 is incredible — smooth, fast, and controllable. Installation took about 15 minutes with no issues. I am a happy man!
dustin –
This is my first Rare Breed product and it absolutely will not be my last. I have never purchased a trigger with a flat trigger shoe but decided to give it a go. It was an easy installation. The semi-auto pull is smooth and consistent and the break is clean every time. And in semi-auto, I can totally appreciate the feel with the flat trigger shoe. Running it in the FRT mode is amazing. The rifle runs fast and smooth without feeling out of control. The platform just eats it up. Super nice and well built!
Landon –
Running the flat variant FRT-MR3 in my MR556. The flat trigger blade is a game changer for this platform. My finger sits more naturally on the flat shoe and the trigger pull is incredibly consistent. The break is clean, the reset is fast, and FRT mode on this platform is nothing short of incredible. Build quality is exactly what you expect from Rare Breed. If you are on the fence about curved vs flat, try flat. You might be surprised.
Kevin T –
I already had the curved FRT-MR3 so I wanted to pick up a flat version as well. The flat trigger blade gives you a different feel and I am happy with it. Not sure which one I like the best though. Standard semi-auto feels better than the OEM trigger and forced reset mode is straight fire. The build quality is top tier and it’s worth every dollar. Thank you Rare Breed!
Andrew –
I have already purchased the Rare Breed FRT-MR3 with the curved trigger blade and couldn’t have been more impressed. It runs ridiculously well in forced reset mode and the quality of the standard semi-auto mode is top notch. I’m not sure how I feel about a straight trigger blade in the HK MR556 platform but after experiencing just how awesome this trigger really is, I might just have to give it a try. Well done guys!
James –
This trigger is badass!