Your firearm is more than just a tool. It’s a beautiful work of art. Each component has been carefully crafted to perform its function, and when you disassemble and reassemble a weapon, you can feel the care and attention to detail that went into its design.
But how do these parts go from a concept in someone’s notes to your firearm? Well, as experts in building and maintaining firearms, we can tell you that it’s a fascinating journey. Today, we’ll start with the basics of one of the largest parts: how rifle barrels are made.
Table of Contents
- Barrel Design
- Initial Trueing
- Deep-Hole Drilling and Reaming
- Rifling
- Air-Gauging and Straightening
- Lapping
- Stress Relief
- Get High-Quality Barrels at Wing Tactical
Step 1: Barrel Design
The first step in how rifle barrels are made is designing the barrel itself. There are a few considerations designers need to make: rifle model, caliber, length, and what material the rifle barrels are made of.
Rifle Model
Obviously, barrels aren’t universal. The firearm model the barrel is made for has to be decided first. Once chosen, this may impact the specs needed for the other three considerations.
Caliber
The caliber of a cartridge describes its diameter. The barrel needs to have the same caliber as the bullets that will be passing through it.
Length
While rifle length doesn’t actually have much impact on accuracy, it drastically impacts who will be able to comfortably use the rifle. A long barrel can shift the center of gravity for the gun outwards, making it unwieldy for smaller shooters. They can also get stuck in brush and undergrowth, which can be frustrating for hunters.
However, longer barrels improve powder burn efficiency, hide muzzle flash, and improve velocity. That’s why sniper rifles have longer barrels!
Material
What rifle barrels are made of is one of the most important parts of how rifle barrels are made. They have to be strong enough to resist the heat and power of modern smokeless propellants, as well as take into account the weight and cost of the material. Most manufacturers use either alloy steel or stainless steel, which have great strength-to-cost ratios.
Step 2: Initial Trueing
Now comes the machining part of how rifle barrels are made. A bar of metal is cut to length and turned on a lathe to face the ends off square. Additional profiles for gas blocks, locking nuts, and other parts are also cut during this stage. To add stress relief, the bar may also be heated at 600 degrees Fahrenheit, then allowed to cool.
Step 3: Deep-Hole Drilling and Reaming
A long drill with a tungsten-carbide bit and hollow stem is lowered into the trued bar. Cutting oil is funneled through the hollow stem to flush metal chips out and keep the cutting tooth cool. The cut must be smooth, straight, and uniform in diameter. This is the most difficult part of the process, and the designer's choice as to what the rifle barrels are made of is most relevant here.
After the hole is drilled, it’s reamed to ensure smoothness and a correct diameter. Barrel makers have to be careful here; chatter marks from improperly used reamers are one of the most common manufacturing defects in firearms.
Step 4: Rifling
The smooth hole now has rifling grooves etched into the bore. There are three common rifling techniques to know for how rifle barrels are made: cut, broach, and button rifling.
- Cut: The oldest form of rifling. Grooves are cut using a cutting tool like a hook scraper.
- Broach: A modern variant of cut rifling. Instead of a single-bladed cutter, a metal bar with cutting blades progressively set down its exterior in spiraled succession is pushed or pulled through the barrel, cutting the grooves.
- Button: A bullet-shaped piece of tungsten carbide with the reverse of the desired groove pattern is pushed or pulled through the bore. This irons the groove pattern into the bore by displacing the metal.
Step 5: Air-Gauging and Straightening
One of the most important parts of how rifle barrels are made is QA. To detect any inconsistencies in the bore diameter, a snugly fit air gauge is pulled through the barrel. The barrel may also have been warped slightly through all the machining processes. A turret press is used to straighten the barrel.
Step 6: Lapping
The bore is plugged with a small bit of molten lead. This plug is coated in lapping abrasive and run back and forth down the bore, leaving the interior with a smooth polish and consistent diameter.
Step 7: Stress Relief
Once completed, the last step in how rifle barrels are made is stress relief. Through either conventional heat treatment or cryogenic stress relief, stresses that can cause warping (like heat) are removed. The likelihood of the stresses occurring depends on what the rifle barrels are made of, with higher-quality materials providing more resistance. This finished and stress-relieved barrel is known as a “barrel blank.”
The barrel blank is chambered, head-spaced, crowned, threaded, and polished. Only then is it ready for us in a firearm.
Get High-Quality Barrels at Wing Tactical
Now that you know how rifle barrels are made, it’s time to order one for yourself. At Wing Tactical, we’re not just passionate about education on our blog. We also offer a vast inventory of high-quality gun parts for you to upgrade your AR-15, Glock, or other firearm. We exclusively offer parts that we would use in our own guns. Reach out to us to learn more about how you can upgrade your rifle.