Calibers and Twists

The information below will help you select the best barrel twist for your specific needs, providing of course there are multiple choices. If you'll be shooting one bullet weight, choose a twist from the chart just fast enough to stabilize it. Too fast a twist simply overspins the bullet and may result in reduced accuracy. So if you're going to be using several bullet weights, be sure to select a twist that will stabilize the heaviest one, since lighter bullets will also be stabilized.

By way of explanation, the numbers in the Twists column indicate how far the bullet must travel through the bore to make one full revolution. This is determined by the rate of rotation of the rifling. For example, a 9" twist barrel spins the bullet one full turn when it travels 9 inches through the bore. In a 16" twist barrel, the bullet makes on revolution in 16 inches. So at the same bullet velocity, the 9" twist is faster (spins the bullet faster) than the 16" twist. Consequently, as the chart reflects in the .224 CF section, the 9" twist is necessary for stabilizing heavier bullet weights.

Again looking at the .224 CF section, if you're planning to shoot 55-grain bullets, the 14" twist is ideal. This twist is also the best choice for 52-and 53-grain match bullets driven at moderate velocities. But if you're also contemplating shooting a 60-grainer, go with the 12" twist, since it will stabilize all the bullets you'll be using. As you can see from the 15" and 16" twists, higher velocities also spin the bullet faster and my enable a slower-than-recommended twist to stabilize a marginally overweight bullet.

As a general rule: The higher the velocity, the slower twist is required. The lower the velocity, the faster twist is required.

This chart outlines the basic principles

Caliber Twist .172 10" For all bullets .22 RF 14"* Twist for pistol barrels 16" Standard twist for rifle barrels 17"* Special twist for rifle barrels .224 CF 9" For bullets heavier than 63 gr. 12" For bullets up to 63 gr. 14" For bullets up to 55 gr. 15"* For bullets up to 55 gr. driven 4,100 fps or more 16"* For bullets up to 55 gr. driven 4,300 fps or more 6mm/.243 8" Special for VLD bullets 10" For bullets up to 120 gr. 12" For bullets up to 85 gr. 13"* For bullets up to 75 gr. 14"* For bullets up to 70 gr. 15"* Special for bullets up to 70 gr. .257 9" For bullets heavier than 100 gr. 10" For bullets up to 105 gr. 12" For bullets up to 90 gr. 13"* For bullets up to 80 gr. 14"* For bullets up to 70 gr. 6.5mm/.264 8" For bullets heavier than 120 gr. 9" For bullets up to 120 gr. .270 10" For all bullets 7mm/.284 9" For bullets heavier than 140 gr. 11" For bullets up to 140 gr. .307 13"* Special size and twist .308 8" For bullets heavier than 220 gr. 10" For bullets up to 220 gr. 12" For bullets up to 170 gr. 14"* For bullets up to 168 gr. 15"* For bullets up to 150 gr. 7.65mm/.311 10" For all bullets .338 10" For all bullets 9mm/.355 14" For low-velocity wadcutters 16" For all other bullets .38/.357 14" For low-velocity wadcutters 18" For all other bullets .358 14" For all bullets .375 12" For all bullets 10mm/.400 16" For all bullets .411 14" For all bullets .416 14" For all bullets .44 20" For all bullets .451 16" For all bullets .458 14" For all bullets *Stainless Steel only

Black Powder Barrels (1.250" x 30") .32 14" .320" groove .38 20" .379" groove .40 20" .403" groove .457 20" .457" groove