Barrel Rifling Basics
It's All About The Spin
If you have ever thrown a football you know that putting a twist on a throw is essential for accuracy and distance. The same concept is true when it comes to modern rifles; every barrel is grooved on the inside in a spiral called “rifling”.
As the bullet travels down the barrel, it rotates along with these grooves. To be able to travel long distances and stay accurate the bullet has to be spinning when it leaves the barrel. Rotation, whether over-rotating or under-rotating, can affect accuracy. Whether shooting an AR or a long range rifle, barrel rifling is important to understand when it comes to purchasing ammunition and finally pulling the trigger.
Determining the Rate of Twist
Measuring rifling in a rifle barrel means obtaining the “rate of twist”. The rate of twist is a measurement that is determined by how many inches of barrel it takes for the bullet to make one full 360 degree rotation. For example, if the bullet has to travel 7 inches to make a full rotation, the rate of twist can be shown as 1:7. If you’re shopping for rifles in a catalogue, you’ll see twist rates included in the back with rifle details. Online, you can usually find rate of twist details for the rifle you’re looking at in the description. Wherever you’re shopping, always make sure to check out the ratio included; that’s your rate of twist, and it can change the way you shoot and the ammunition you are using completely.
Using Rate of Twist on the Range
The type of shooting you are doing will determine the type of ammunition you should want. A faster rate of twist will require a heavier bullet; the faster the bullet the more wobbly and unstable it can be. Shorter, lighter bullets require less spin to stabilize, so slower rate of twist barrels are preferable. You can overrotate a bullet, which can affect accuracy, so it is important to select ammunition that will work best for the twist rate of your barrel. For long range shooters, reloading can be a great option to achieve the perfect load for your twist rate.
Your barrel should be treated with just as much care as any other part of the rifle, especially if you’re trying to achieve the perfect shot at long distances. To remove some of the tool marks left by the manufacturer, check out the Wheeler Bore Lapping Kit that makes it easy to get your bore ready for the perfect shot. Regular maintenance and cleaning your barrel is important; use a Wheeler Universal Barrel Clamp to work on your barrel.