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Only as Good as the Barrel
When building a rifle, get the best barrel you can afford
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There are many companies that make custom rifles, but very few that make the barrels for their rifles. Modern barrel making is a task that requires very expensive, specialized machinery.
Smoothbore barrels are not complicated, but adding rifling complicates the task immensely.
There are two modern methods to creating a rifled barrel. One method is to bore a precise diameter hole through a steel rod and then draw a rifling cutter or hardened swaging tool through the bore. It requires many passes to use the cutter to bring the rifling grooves to a uniform depth. Many times, the hole drilled for the bore is not straight. In this case, the barrel must be straightened. The straightening is done on a barrel press and produces a barrel that will be acceptable for most hunters. After a few shots, the point of impact will begin to wander, as the barrel stress relieves when it becomes heated from subsequent shots. The point of impact from these barrels will return when the barrel reaches ambient temperature. Very accurate barrels will not be straightened and are closely examined at the factory for any rifling defects. These barrels are usually called “Premium” and the best of the best are “Air gauged” for quality.
The swaging device usually only has to be drawn through the bore once. The swaging tool displaces the bore’s metal and creates a rifles bore quickly. Another type of barrel swaging is accomplished by slipping the bored rod over a “Reverse rifled” mandrel and putting the barrel through a rotary hammering machine.
The machine’s multiple hammers strike the heated barrel from all 360 degrees. As the hammers compress the barrel, it takes on the form of the rifling from the mandrel. This is called a “hammer forged” barrel. Because these barrels are made when they are very hot, there is little “stress relieved” during firing.
In summary, when building a rifle, get the best barrel you can afford. You will not be sorry. The accuracy of a firearm is determined, in large part, by the barrel.