Everything You Ever Wanted To Know About Rifle Barrels But Were Afraid To Ask

Fred Feddersen is a true student of better lapping, hole boring, bullet flight and rifling. For Feddersen, it’s not just a business, it’s an obsession with building barrels that deliver single hole accuracy.

Everything You Ever Wanted To Know About Rifle Barrels But Were Afraid To Ask

You might not know it, but in much if the firearms industry, products are made by a handful of relatively unknown companies who sell bolt carriers, handguard extrusions, receiver forgings and miscellaneous — and in this case, barrels — to many of the most famous gun companies.

Feddersen is one of those brands that manufacturers top tier barrels for military, OEM and its own sales.

Owner Fred Feddersen is a true student of better lapping, hole boring, bullet flight and rifling. For Feddersen, it’s not just a business, it’s an obsession with building barrels that deliver single hole accuracy.

And to think that Feddersen’s background is in the blow molding process for PET bottles. He now puts all that brainpower to work to help our groups get smaller on the range.

Feddersen is one of those people who can download two straight hours of doctoral thesis level information on firearm accuracy to a group of industry experts and finish with the comment “... And that is just scratching the surface of the problem.”

Fred Feddersen — also known as “GunBarrels.net” or “1022rifle.com” — makes arguably the most consistently accurate production .50BMG, AR15, AR10 and Ruger 10/22 barrels in the industry. Sure, a lot of people claim to be the best. But a Feddersen barrel owns several of the lightweight .50 BMG world accuracy records to back it up.

His newly introduced and heavily OEM’ed AR15 and AR10 barrel blanks consistently deliver .25 MOA groups or better, and Feddersen’s $165 drop-in Ruger 10/22 barrels and complete 10/22 rifles shoot sub-quarter inch 50-yard groups with just CCI SV ammo. Now the company is developing .510 Beck rifle barrels and pistol barrels for Glocks and 1911s.

Feddersen accomplished this accuracy feat across this wide array of calibers by inventing and patenting a new type of rifling called SEPR, or “Single Edged Polygonal Rifling.” The SEPR rifling is also paired with Feddersen’s unique lapping and boring process, which produces a straight and glass-smooth rifle bore.

Grand View Outdoors: How big of a problem is accuracy in the industry?

Feddersen: People are making unbalanced bullets and crooked bores. A crooked high runout bore makes crooked rifling that delivers a bullet that cannot stabilize properly in flight. Unbalanced bullets obviously have the same problem. Ideally a shooter wants the straightest barrel, with the smoothest rifling, the least bullet deformation during chambering, with the most concentrically round and perfectly balanced bullet available. … My goal in life has been to work through each of these points to strive for single hole accuracy.

GVO: Is technology the problem?

Feddersen: The three main barrel-making processes are hammer forging a rifled bore mandrel around steel to form the barrel, a standard boring process of a steel blank with a cutting bit, and then hybrid manufacturing processes which bore and then attempt to reduce imperfections after the boring process with reaming or lapping. Most companies are still using the very old standard boring process which is riddled with problems. For the most part manufacturers are willingly using an old and inexpensive barrel making process either because of cost or because they really do now know any better. Hammer forging or the prefered hybrid barrel making process is considerably more expensive both in labor and from an equipment perspective.

GVO: How is your boring process different?

Feddersen: We strive to start with the straightest bore in the industry. If the boring process does not deliver a perfectly straight bore, then it is said to have “bore runout.” Some people joke that it is a measurement of how straight the banana is. Nearly everyone cuts bores with the barrel blank spinning with the cutting bit remaining stationary. The problem is that the barrel whips back and forth just a bit in the middle as the bore is cut. At the same time, the bit wanders in a circular corkscrew pattern as it hits hard and soft areas of metal. All the barrel manufacturers are attempting to minimize this. The more the bit wanders around the centerline of the steel barrel blank as the bore is cut or the more the blank whips back and forth during the boring process, the more runout you have and the less straight the bore is.

GVO: What makes your SEPR rifling so accurate?

Feddersen: Our six land and eight land SEPR rifling is polygonal on one side with a driving band on one side. It helps to keep the bullet centered on its center of mass during the chambering and firing process which reduces bullet deformation and delivers a bullet that tracks straighter. Bullets do not fly straight out of anyone’s barrel, but we are all attempting to improve that. Bullets both corkscrew and sway out of a barrel. Corkscrewing is when the bullet rotates around the center of mass of the bullet as they spin through the air similar to an out of balance car tire. Sway is when the bullet behaves like a badly through football that wobbles. Our patented rifling reduces the propensity of bullets to corkscrew and sway.

GVO: How much do quality bullets impact accuracy?

Feddersen: All the top bullet manufacturers are making better and better bullets. Copper plated bullets fly straighter than copper clad bullets, and monolithic all copper turned bullets are the best overall performers due to their balance and concentricity. If the bullet is not perfectly round, balanced and ballistically flight optimized, the best rifling in the world will not fix that problem.

GVO: When it comes to barrel accuracy, are the bullet balance and consistency more important than bullet weight?

Feddersen: Yes and no. Lighter bullets are not affected as much by a poorly designed barrel or unbalanced center of mass as heavier bullets, and this is why we see most .223 50gr bullets do so well when being over-spun even in 1:7 twist barrels. The heavier the bullet, the larger and more dramatic the corkscrew effect is in flight of the bullet to compensate for the balance issues.

GVO: So we can blame most of the issues on poorly designed bullets?

Feddersen: Actually, today we have really great bullets if you spring for the premium brands as a shooter. It may not be the bullet’s fault that it is out of balance. Most rifling greatly smashes and deforms a perfectly good bullet, or worse, does not concentrically align it to the bore. The result is a good bullet being smashed and deformed into something that will fly funny. More of the blame is usually with the barrel, considering the quality of ammo we now have available. An easy way to test this is to shoot very high grade turned monolith copper bullets like those that target shooters use. If you still see poor performance, the culprit is likely the barrel not the ammo.

GVO: How does bullet speed impact barrel accuracy?

Feddersen: Speeding up or slowing down the bullet or changing its initial acceleration or distance traveled all impact how noticeable that out of balance flight rotation is. This is why we see the same bullet out of the same rifle deliver really good or really horrible accuracy with different handloads with just powder or velocity changes. The same is true for the ballistic optimization of the bullet. Better bullets reduce variations in flight which deliver better accuracy. Hornady just noticed that ballistic enhancing tips are melting in some cases, and they’ve remedied that problem. Bullets are getting better.

GVO: how important is the barrel crown?

Feddersen: Each and every part of the barrel is an important component impacting accuracy. Perfectly crisp, concentric, perpendicular barrel crowns are extremely critical to accuracy. Obviously if you have a high runout crooked barrel, the crown will be ever so slightly out of perpendicular alignment and makes the bullet flight funny. The crown should give the bullet a perfectly concentric exit point and also deliver a perfectly concentric muzzle blast to maximize bullet speed and flight stability. The muzzle blast is what maximizes bullet speed. One of the reasons suppressors help improve accuracy is that they help to stabilize and correct a potentially poor and inconsistent muzzle blast, which in turn improves bullet flight and accuracy.

GVO: We hear often that you have to have a long barrel to maximize barrel accuracy?

Feddersen: Most of the world’s best shooters have barrel lengths that maximize powder burn to maximize velocity, which then helps to improve accuracy as ranges increase. Barrel harmonics also come into play. As the bullet travels down the barrel from an explosive charge, there is a natural vibration or resonance. We saw this while testing the 10/22 barrels. Our 16.25-inch barrels were actually outshooting our 20-inch barrels with CCI SV ammo. After experimenting with various cut down lengths we found that certain lengths are harmonically balanced to certain rounds. Ideally we attempt to optimize both length and harmonics in our designs.

GVO: What should a retailer and customer know about upgrading barrels?

Feddersen: All commercial barrels are made fast and inexpensively and they may have chamber, rifling, bore and crown issues as a result. If a customer is set on really upgrading a barrel to maximize accuracy, the best advice I can give is to not purchase based on price but on earned reputation. Brands like Lilja, Shilen, Lothar Walther and our Feddersen barrels are not mass produced, but crafted to a higher attention to detail through exhaustive hand reaming, lapping processes and with deep investments in precision manufacturing technology. In most cases we see the best barrel manufacturers in the world using some type of lapping process, so I would encourage accuracy-hungry customers to look for manufacturers who make barrel with this technique.


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