Yup, we thermal fit our barrels to the uppers. You might be wondering, what exactly is thermal fitting? Let me break it down for you. We don’t just slide the barrels into the upper and secure them with a barrel nut, where even tiny movements can affect the accuracy from shot to shot. That may be cool for mass produced rifles that are ok with 2 MOA or worse accuracy. That’s just not who we are. Instead, we intentionally mill the barrel seat to be slightly smaller than the barrel extension that fits into the upper.

So, how do we get the barrel in place? That’s where thermal expansion comes into play. When metal heats up, it expands. We heat the upper to make the metal expand, allowing the barrel extension to fit snugly inside. Once the upper cools down, the metal contracts and locks the barrel in place, ensuring there’s absolutely no movement, even during high-volume firing.

This, combined with our use of extremely high-quality, precision barrels, is how we achieve SubMOA accuracy in our rifles. Science is pretty awesome, isn’t it?

Mitchell Defense Enhanced Buffer System

At Mitchell Defense, we’ve engineered our Enhanced Buffer System to deliver unparalleled reliability and performance. Here’s what sets it apart:

1. 7075 Buffer Tube: Our buffer tube is crafted from high-strength 7075 aluminum, ensuring durability and a solid foundation. We’ve redesigned the feed lip to eliminate the gap between the buffer tube and the bolt carrier group (BCG) when the firearm is chambered, significantly improving feed reliability.
2. Extended Feed Lip: The feed lip on our buffer tube extends past the retention pin, creating a locked-in buffer tube that cannot back out, even if the castle nut becomes loose. This design provides added stability and ensures your system remains secure and reliable.
3. Enhanced Buffer Spring: Our buffer spring is a flat wire spring with a specialized metal treatment that increases forward pressure. This results in reduced felt recoil and better management of muzzle rise. The spring’s design ensures an even distribution of force during the compression cycle and consistent forward pressure during the bolt return, eliminating the inconsistent tension found in basic carbine springs.
4. Unmatched Durability: Our enhanced buffer spring is designed to operate at top capacity for over 200,000 rounds. Compare this to a standard round wire spring, which typically degrades after just 8,000 cycles. This means our spring will keep your firearm running smoothly for much longer, providing you with the reliability you need.

Why Reducing Friction in Rifles is Crucial

At our core, we believe that Friction = Heat, Heat = Wear, Wear = Failures. But what does this mean for a rifle, and why is it so important to minimize friction?

In any mechanical system with moving parts, friction is the primary enemy of longevity. This is a lesson we’ve learned well from the oil field, where the constant movement of parts can lead to significant wear over time. In a rifle, the bolt carrier group (BCG) is the key moving component. Each round that cycles the BCG back and forth adds to the wear on both the upper receiver and the carrier itself. Over time, this wear can accumulate to the point where it causes failures, affecting the reliability and performance of your rifle.

One of the most critical aspects of friction is its tendency to attract dirt and debris. In a direct impingement rifle, the gas system continuously introduces carbon and other residues into the mechanism. High friction surfaces make it easier for these contaminants to stick, leading to increased resistance and potential malfunctions. By reducing friction, we ensure that your rifle runs smoother, with less carbon buildup and resistance, which means it’s less likely to fail during critical moments.

Additionally, a low-friction surface makes cleaning your rifle much easier. Who doesn’t appreciate a cleaner, more maintainable firearm?

To achieve this, we’ve taken a multi-faceted approach. We coat the BCG with a specialized coating called Armorlube, which has a friction coefficient of less than 0.1—the lowest possible on the scale for measuring friction. This coating not only reduces friction but also handles heat exceptionally well, eliminating the need for chrome lining. Many coatings claim to have low friction coefficients, but they often degrade under high temperatures. Armorlube, on the other hand, remains stable and effective even under extreme conditions.

We don’t stop there. We also coat the inside of the upper receiver with a coating that matches the low friction coefficient and has the hardness to withstand constant movement. By doing this, we’ve virtually eliminated friction between the BCG and the upper receiver.

Every part of our rifles is designed with longevity in mind. Even the gas rings are coated to ensure they perform optimally over time. By minimizing friction at every point, we’re not just extending the life of your rifle; we’re ensuring it runs smoothly and reliably, no matter the conditions.

Accuracy is one of the three pillars that must be in place for a rifle to be called a Mitchell Defense Rifle. When using your rifle for any intended purpose, it should hit the target where you aim it, not three inches to the left. This is why we offer a SUBMOA guarantee on all our rifles. We firmly believe this should be the standard every company is held to.

There are many factors that go into shooting accurately, and your equipment shouldn’t be one of them. Every component plays a crucial role in ensuring your shots are on target. We take this seriously, which is why we meticulously design and test each part of our rifles to meet the highest standards of performance.

Reliability is another essential pillar required in all Mitchell Defense rifles, and it is near and dear to our hearts. No matter the situation, your rifle must go bang, especially in life-or-death scenarios. We take exhaustive measures to ensure our rifles perform reliably in this critical area. From locking the barrel in place to removing friction points and enhancing the effectiveness of the buffer system, we have created one of the most reliable ARs on the market today.

Our latest independent endurance test ran 17,554 rounds through the rifle before we experienced our first failure. That’s several thousand rounds more than what is considered high-performing. We are committed to ensuring that when you need your Mitchell Defense Rifle, it will be there for you without fail.

Durability is another of the three essential pillars of the Mitchell Defense Rifle. It has to go straight and it has to go bang, but if it falls apart on you, it’s all for nothing. Each and every part of our rifles is inspected and tested to ensure it will last the lifetime we promise. Yes, there are still some wear parts, but we take every step to extend their life as much as possible. Every rifle we build is crafted with the hope that it will be passed down through generations.