The next time you’re cleaning your Glock 19 barrel, shine a bore light down it through the chamber end and take a look. You see the rifling?
That rifling has a very specific rate of twist, also known as twist rate, that’s critical to bullet stability and accuracy.
This short post will break down the details.
What Is Rate of Twist (AKA Twist Rate?)
Rate of twist, also known as twist rate, refers to how far down the barrel the bullet must travel in order to complete one revolution.
Twist rate is given as a ratio between two numbers. For instance, in our Glock 19 barrels, twist rate is 1:10, which means that a bullet must travel 10 inches through the barrel to complete one revolution, that is, to spin once fully.
The lower the second number, the faster the bullet will spin, and the higher the second number, the more slowly it will spin.
We cannot understate how important twist rate is to bullet performance, consistency, and accuracy.
How Does Twist Rate Impact Accuracy?
Fast twist rates are usually associated with longer, thinner bullets and faster burning powders. This is why cartridges like .223 Remington, which are loaded with thin spitzer bullets and which can produce muzzle velocities above 3000 FPS, usually are fired from barrels with 1:7, 1:8 and 1:9 twist rates.
On the other end of the spectrum, muzzleloading rifles firing fat, round patched balls over much slower-burning black powder have far less aggressive twist rates. A common muzzleloader twist rate is 1:48, which means the ball or bullet would need to move 4 feet (48”) through the barrel to spin one time.
Slower burning powders and round bullets do better with slower twist rates, whereas spitzer bullets and hotter burning powders require a faster twist to stabilize the bullet in flight. It’s also worth noting that the design of the latter (pointed bullets) is better for accuracy, regardless of twist rate.
That is, you can shoot a .223 Remington rifle more accurately at 300 yards than a 9mm carbine, no matter the load data, barrel length, or twist rate. One is designed for intermediate and long ranges, and the other isn’t. But you still need to keep twist rate in mind in order to deliver on the best overall performance.
The ideal twist rate will also be determined in part by the weight of the bullet. As a general rule, heavier bullets need faster twist rates and lighter bullets perform better with slightly slower twist rates.
So there’s a lot to balance here in terms of powder deflagration, chamber pressure, bullet size, shape, and weight.
The 9mm bullets fired through your Glock 19 barrel are fairly heavy and fairly wide, but muzzle velocity and chamber pressures are on the low end as cartridges go. So they’re benefited best by a twist rate that is somewhat in the middle of the road.
We also recognize that shooters shoot a whole wide range of different 9mm Luger loads. You could be shooting lightweight 115 FMJ target loads, or heavier, 147 grain hollow points that are faster, too.
We needed to split the difference. The Gen 5 Glock 19 comes with a barrel that has a 1:9.84” RH twist rate. Our Glock 19 barrels have a 1:10 twist rate that we determined offers the best performance across all of the different 9mm Luger loads you’ll encounter, from the lightest range ammo to the hottest, hardest hitting defensive loads.
Our Glock 19 Barrels and Performance
The 1:10 twist rate is not the only defining feature of our G19 barrels, notwithstanding the fact that this twist rate is instrumental in guaranteeing the best overall performance regardless of the type of bullet you’re shooting, or the load data.
Our G19 barrels are also fluted, either with pentagonal flat fluting or spiral fluting, which helps aid in the barrel’s heat dissipation capabilities, while also lightening the overall weight of the barrel, for a lighter overall carry weight and less fatigue during long days.
With an eye on recoil mitigation, our Glock 19 barrels are also available in threaded configurations so that they can be paired with muzzle devices such as compensators or suppressors, both of which will substantially reduce felt recoil and muzzle flip, enabling more confident, accurate shooting, and faster, more accurate follow up shots.
While our Glock 19 barrels do represent a significant upgrade that you can make to your G19, they are only one of a handful of upgrade parts that we offer here. Consider our catalog of Glock 19 slides, barrels, magwells, sights, triggers, and other parts and accessories and contact us directly if you have any questions about specs, part or model compatibility.
