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  • Added on: December 03 2012 07:16 PM
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Review/How-to: Clint Beyer Barrels - Match AR Barrel

Posted by jetspeedz on December 03 2012 07:16 PM

I decided to build another custom rifle and set my goals to build a very unique match AR. Having already built a match AR-15 I decided to build a match AR-22 this time using nothing but the highest quality parts made in the USA. Building an accurate rifle requires precision made component and nothing is more important than a quality match barrel. There are only a few names which come to mind when considering this option, Clint Beyer Barrels is one of those names. When it comes to accurate .22LR barrels, Clint Beyer makes some of the finest match barrels available today. Clint offers a variety of match .22LR barrels for different platforms including the AR.

Clint Beyer retired from the Military and set his sights to pursue his passion in the firearms industry. Being an avid hunter and vast knowledge of various machines he started Beyer Barrels in 2006. Since than he has put out precision quality products which have got the industries attention, companies like Brownell’s carry his barrels in their catalog. Clint is flexible in making a custom barrel to suit your specifications and being easily reachable makes it a pleasure to work with him. Each barrel, custom or not is hand made with precision machines and the craftsmanship shows. Clint does not take any shortcuts and takes a lot of pride in his work. All of the materials used to make his products are from the USA. The barrel I received was exceptional and performed as well as any match barrel should.

There is so much information about how a barrel is made one could write a book. For the sake of keeping this article from turning into a book I will focus on what Clint offers and the processes used to make his barrels. Like the rest of my custom build having a match barrel made in the USA was important to support our manufacturing here in the States. Clint starts of with aircraft grade aluminum 7075-T6, which is more durable than 6061. I went over this in the Mega Arms receiver review if you want to know more about the difference of the two alloys. Using 7075-T6 allows for better heat dissipation than softer alloys while retaining strength, and has higher corrosion resistance properties. Weight being a key factor in my build, I was pleased to see Clint offering a light weight combination aluminum barrel, compared to my match .223/5.56 stainless steel fluted SDM-R barrel. The bar stock aluminum is setup in a CNC lathe which is used to turn the outer surface of the barrel, than another lathe is used to ream the bore of the barrel. This is the starting foundation of the barrel, from there the barrel is cut down to size to meet specifications. Clint makes custom match chambers for these barrels, they are close to the Bentz reamer dimensions, but his reamer is custom with tighter specification which is proprietary. The Bentz chamber is well known for being a top match chamber for semi-automatic .22LR rifles. Match grade chambers give specific ammunition the best performance due to the very tight tolerances, measurements such as headspace, length of chamber, mouth/throat diameter and taper at the throat are critical in a semi-automatic configuration. I have included some charts with reamer dimensions and specifications for reference. Clint can also modify the chamber to accommodate any type of .22LR ammunition. Not all .22LR ammunition is created equal, you can see from the diagram I included the dimensions of a standard .22LR ammunition. Clint’s standard chamber will work with just about most off the shelf ammunition, however there are some .22LR ammunition which use longer casing such as CCI Stinger (0.09-0.1” longer case), which will require a modified chamber which Clint can accommodate at your request. Choosing the right ammunition is just as critical for accuracy, Clint himself has had great success with CCI Standard velocity ammunition up to 300 yards consistently. I used a variety of .22LR ammunition and some group better than others.

I opted to have a muzzle brake made for the barrel to match the outer diameter of the barrel (.920) for a finishing touch. The brake is 1.75” in diameter and the overall length of the barrel with the brake measuring from the end of the upper receiver is just about ~16.5”. The barrel was threaded on CNC lathe and the custom muzzle brake was also made form 7075-T6 aluminum on a CNC. There is a video on Clits website which shows how the brake is made from start to finish, it exhibits the level of detail required to program such a piece (http://beyerbarrels.com/videos). After the bar stock is turned and reamed the unfinished barrel is prepped for a 4140 Chromium-Molybdenum steel referred to as chromoly steel rifled liner. Clint uses 4140 liner for various reasons, but the main reason is availability. There are a variety of metals used to make barrels, but the most common type of match grade barrel are made from a variant of chromoly steel or variant of stainless steel. There are some differences between the two metals, in terms of final finish, stainless barrels can not be blued as easily as chromoly. The metallurgy between stainless steel and chromoly is similar in many ways however one major composition mass which differs in significant quantity is chromium levels in stainless steel. This makes stainless much more resistant to corrosion. If you do not live in a dry climate chromoly barrel is more likely to rust. In all high strength steels, toughness and fracture resistance diminishes as the temperatures falls. Chromoly is generally harder than stainless so the barrel profile can be smaller. 4140 chromoly can withstand higher temperatures before deforming compared to 416 stainless steel. Using 4150 chromoly is even more tolerant than 4140 and a combination of 4150 chromoly with vanadium is the most tolerant which is used for full automatic barrels supplied to the Military. However they are not as accurate as match rifles due to the hard chrome lining. Clint’s decision to use 4140 work for those shooters who use a variety of ammunition made from various metals, as it is less susceptible to fouling. However, stainless will wear slower and retain its accuracy over chromoly, specifically in the throat of the barrel, due to resistance of burning powder because of higher copper composition. Metallurgist will tell you barrel life depends on a lot of factors from wear, fatigue and environmental conditions. When it comes to choosing between stainless and chromoly for match grade barrels there is no right answer. The source of the metal and the process used to make the barrel is just as important. Metals coming from overseas are part of the problem these days with consistency and quality of mass produced barrels. Clint buys the bar stock materials directly from sources in the USA to provide the highest quality control possible.

Clint custom orders these barrels liners which are made by button rifling method. There are three basic methods for rifling a barrel, cut, button and hammer forging. Each method is used for custom barrels and each has their advantages over the other. Cut rifling is the oldest method and basically involves cutting the bore with a cutting tool and removing small amounts of material with each pass, while rotating the tool to create the desired twist rate. Some manufacturers’ use broach rifling, which is similar to cut rifling, it is faster as it only requires one pass through the bore. This is done by using a progressive cutter, but it is costly to make the cutter and must be sharpened often. Hammer forging is the least common method for making barrels due to the high cost of equipment. Essentially the rifling is done by a machine which pounds the barrel to form the rifling, while sometimes also contouring the outside of the barrel. The most common method is buttoning which Clint uses. All my match barrels are made using this method, it seems to be a favorite among custom barrel makers due to cost and consistency. A button, which is a football shaped carbide tool attached to a rod, is either pushed or pulled through a slightly undersized bore to create the rifling and twist rate. It is important to understand when the button is pushed or pulled through it is not really cutting material, but it is ironing the bore as it hardens and smoothes the bore, leaving a mirror like finish. The benefit of this cold forming process is forcing the grains of the metal to conform to a directional fashion putting stress on the metal which can be good, if done properly to help strengthen the metal. There are two schools of thought when it comes to push or pull button rifling. The advocates for pull say it is easier to keep the button straight and true as it is pulled through the bore. When pushing, there is a chance the button can walk away from the axis. Each barrel maker will give you their opinion on their method and frankly there is no wrong answer as long as the end result is uniform. I do know all my match barrels have been made using pull buttoning for what its worth. Once the buttoning process is complete, the barrel or liner needs to be stress relieved otherwise it will possibly deform or split during firing. This is done by heating the barrel or liner in a furnace and slowly letting it cool down. Clint uses a thermal stabilization process, which is proprietary. Clint goes as far as lapping the chamber after the liner is stress relieved, this is critical for an accurate barrel. However from his experience, he does not lap the liner, as it is already smooth and uniform. Lapping is a process which involves polishing the surface while removing any imperfections and making sure the area is completely uniform.

When it comes to twist rate, for the most common .22LR ammunition, a 1:16 twist rate is optimal. The length of the bullet really determines the twist rate, given a specific caliber. Too much twist is just as bad as not enough twist to keep the bullets trajectory as true as possible. Since most off the shelf .22LR ammunition are made to standard specifications, using one turn in sixteen inches is the best twist rate for stabilizing the bullet as it leaves the bore. If the bullet is longer, or made from a different material which increases the weight, than more twist is required, but most off the shelf ammunition will work with a 1:16 twist rate just fine. The process used to mate the liner to the barrel is proprietary, it is one of the factors which sets Clint’s barrels apart from the competitors. Normally a liner is shrink-fitted, soldered or glued in place using various techniques. Barrels made for low pressure calibers like .22LR are made with liners for weight reduction. One concern about using a chromoly liner and aluminum outer shell is linear thermal expansion. 7057-T6 aluminum (23.6 1E-6/K) vs. AISI 4140 chromoly steel (12.2 1E-6/K) {source: American Society for Metals International}, clearly shows the rate of expansion for the chromoly liner is lower than aluminum outer body. Clint has thoroughly tested his barrels, there is no need for concern with regards to the liner coming apart or deformation. Clint oversized the barrel shank by 0.001” for a tight fit, which might require sanding on certain upper receivers, on my Mega Arms billet upper, it was a perfect match, with a little bit synthetic lube I forced it right in without issues. Clint spent a lot of time converting .223 adapters to a dedicated collar, but now he uses CMMG dedicated collars for his barrels. Clint offers a variety of barrel sizes for the AR platform and can set them up with gas blocks if you desire. He can thread any barrel to accept muzzle brake, flash hider, or silencer. Typically he will thread 1/2"-28 TPI for standard AR-15 applications.

Clint’s barrels come with a variety of crown options, the AR line of barrels normally come with a recessed target crown to protect the rifling, which makes it versatile for a variety of activities and outdoor use. If you opt to use his custom muzzle brake or thread protector, he cuts a 11 degree crown on the threaded end for added insurance. Clint uses a piloted crown reamer on the barrels. On a standard bull barrel, he normally cuts a recessed 11 degree crown, which is a favorite among shooters. When it comes to muzzle crowns, there are a variety of options and some have a specific purpose while others are purely aesthetic. The popular 11 degree crown has become an industry standard, however PhD’s have studied the affects of crowns on bullet trajectory and accuracy, coming to the conclusions which does not support the industry standard. The main purpose of a crown is to protect the rifling, but also in theory to allow a smooth transition into ballistic flight. When propellant gases escape the barrel, it takes the path of least resistance. When a crown is perfectly uniform and perpendicular to the bore, it allows the bullet to escape the barrel in the truest form. If a crown is damaged or not uniform, the projected path of the bullet is skewed as the escaping gases will force the bullet to exit the muzzle unevenly. It is very difficult to predict the flawed path the bullet will travel, it depends on the damage to the crown, such as burs or unevenness. Always check the crown for damage and erosion from gas pressure. People don’t realize damage to the crown can occur by improperly cleaning the barrel. Cleaning from the breech end of the barrel and using jags made from softer material than the bore is critical. Some crowns have a chamfer which will allow your cleaning tips to re-enter the bore easier. Clint cuts a 11 degrees crown because it is accepted as the norm and customers favor it. There are stories the Army tested various crowns and came to the conclusion the 11 degree target crown yielded the best groupings and thus the industry adopted it. However due to contrary beliefs, the angle is not significant, the uniformity of the cut regardless of the angle is what matters. As long as the crown perfectly uniform to the axis of the bore, and the gases escape evenly around the circumference of the bullet, the angle is irrelevant. A lot of match shooters prefer 90 degree cuts, so keep that in mind when you hear about “11 degree target crowns”. Clint makes a custom 45 hole muzzle brake, which is a work of art and shows the precision in his machining code. On larger caliber rifles, a brake is used to reduce recoil, while also helping with faster follow up target acquisition. On a .22LR recoil is not as significant, the brakes main purpose is to stabilize the barrel during rapid fire sessions. Typically muzzle end devices like flash hiders and brakes have a larger port than the given caliber they are designed for. This is done so the bullet does not touch the device as it exits the barrel, which could be catastrophic if the diameter is undersized. With a slightly bigger hole by hundredths of an inch, it allows for adequate back pressure. The benefit of buying Clint’s brake is he knows the exact specs of his bore, this allows him to maximize the efficiency of back pressure to propel the bullet in its projected path, while redirecting gases efficiently to reduce recoil and stabilize the barrel. The reason some brakes work well and some don’t is because manufacturers in order to avoid liability issues tend increase the hole diameter slightly to avoid bullet to brake contact, but the adverse affect is redirected pressure, which takes the path of least resistance and exits around the bullet past the brake bullet hole toward the front, adversely feeding more felt recoil to the shooter as opposed to escaping through the diverted brake ports. Without getting entrenched into physics equations, the felt recoil from any brake depends on propellant gases from the bullet and initial force on the gun. Given identical .22LR bullet velocity, the lower grain ammunition will have more felt recoil, by using power factor formula in relation to momentum (PF = velocity x bullet weight (grains)) this can be confirmed. The affectivity of Clint’s brake will be obvious as you test different ammunition with and without the brake. Clint can also coat the brake to match the same finish of the barrel if you desire.

When it comes to barrel options and finishes, there is no other place where you can get the flexibility Clint offers. The variety of finishes include Cerakote Firearm Coatings and KG Coatings, which was originally developed for Military and Aerospace applications, it has become a firearms standard for coating. I can understand why, because this stuff is very durable against corrosion, scratches, surface wear and as I found out chemical resistant, which I’ll explain later. You can read more about the coatings and color pallets on their website. Clint normally uses KG Gun Kote for the brushed stainless finish, which is what I received, and it is prepped by sandblasting the aluminum before it is coated. After coating, it is baked in a custom digital controlled oven at his facility. The primary matte black finish Clint offers is Cerakote, which goes through the same process. If you have a desired color option offered by those two companies, Clint can accommodate your needs. However, it is not possible to anodize the barrel, since the liner is steel, you can not anodize steel. I initially received the barrel with KG Gun Kote brushed stainless, which was a misunderstanding between Clint and myself on the finish. I was able to remove the coating and get a natural aluminum finish, only after sanding the finish off since even the harshest Aerospace grade paint stripper did nothing to the finish, which is pretty amazing. I left the KG Gun Kote finish untouched around the chamber and the crown for the added protection and benefits of the coating. The natural aluminum finish is a personal preference of mine, it matches the natural stainless finish of my match AR-15 barrel and I take extreme care of my firearms. Among the different color options, Clint also offers fluting, which can be done in straight or diamond patterns. He can also paint them or leave them unpainted depending on your desired finish. Fluting has a few purposes, but it is important to understand the benefits and common misconceptions as well. If nothing else, a fluted barrel aesthetically looks good, but it can come at a price if not done properly. Barrels are usually fluted at the request of the customer for weight reduction. This is great for those looking to meet minimum weight requirements for competition matches on longer barrels. Since Clint uses button rifling, to properly flute the barrel, the rifling must be complete and stress relieved before fluting, which prevents damaging the bore uniformity. The common misconception about fluting is stiffness and cooling. With regards to how flutes help with cooling of the barrel, it is very simple. Depending on the depth of the flutes and diameter of the barrel to begin with, the flutes are like heat sink fins. If there is adequate airflow, it will cool down the barrels bore faster. It is critical to know the barrels minimum safe thickness before fluting is done, otherwise it can affect the barrels integrity. Clint has performed the proper stress tests to know what these thresholds are, so before you consider fluting your barrel, keep in mind there are reasons why some barrels are not fluted. Several factors must be taken into consideration with regards to flutes affect on cooling. Using the law of heat conduction for cylindrical objects referred to as Fourier’s Law, it is easy to calculate the efficiency of flutes. The closer the flutes are to the heat source, the faster they will heat up, and theoretically cool down given adequate airflow. Keep in mind, just as quickly as it cools down, it also heats up faster, because there is less material to disperse the heat, so a barrel given the same diameter which is not fluted will take longer to heat up, however it also takes longer to cool down, since more of the heat is insulated within the mass of the barrel. Fluting does not increase surface area per say, as a lot of people believe. If the barrel diameter is bigger than the comparison barrel, and it is fluted to reduce weight and cool faster, than yes it has increased surface area, but if the barrel is compared to a barrel of the same diameter and length than the surface area is actually reduced for the fluted barrel. The same can be said when it comes to barrel stiffness. If a barrel which has a lager diameter is fluted to reduce weight to match the weight of the smaller diameter barrel, than the fluted barrel is stiffer theoretically. When making these comparisons it is assumed the barrels have the same metallurgical composition mass. When referring to barrel stiffness, it is important to understand deflection in Engineering terms, which is related to area moment of inertia. The moment of inertia is property of the materials cross section which is used to predict deflection angles around the axis, which lies in the plane relative to the cross section. Basically when a barrel bends, it creates an arc and the smaller the diameter, the less force needed to deflect the barrel to a given angle. The same force applied to a thicker barrel will not deflect to the same angle, thus a barrel which is fluted and has the weight as a non fluted barrel will be stiffer. It is also worth while mentioning the barrel harmonics will change as you flute a barrel. Fluting must be done using proper tooling, otherwise the metal can be stressed and actually weaken the integrity of the metal, which is why only some manufacturers offer this option.

When I first contacted Clint he was more than gracious in taking my call and answering my questions. With regards to customer service, Clint takes pride in being reachable if it is by email or phone anytime. In an industry where calls and emails go unanswered often this says a lot. Clint offers high quality barrels with precision details which can be custom made to suit your needs. Whether your platform is 10/22 or AR, he can do it all. Clint is one of the few barrel makers, which will offer this level of customization. I could not be happier with this barrel and the accuracy achieved. I would highly recommend a Clint Beyer barrel to any enthusiasts looking for the best match .22LR barrel.

Clint Beyer Barrel Video:


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