Our take on twist rate

With the ever growing popularity of the AR platform on the rise yet again here's a question that gets brought up almost every time someone new to AR platforms purchases one: What are these numbers on the barrel? Often seen as 1:8, 1:9, 1:7, ect. Those numbers happen to be the mark of the twist rate on that specific AR. Almost always the follow up question is, What's that and what does it matter? Well the twist rate of the barrel on an AR platform is a very important detail when choosing one because it will affect your accuracy and selection for the best ammunition to shoot! To simplify it your twist rate refers to the number of times your bullet spins per inch of barrel length, for example 1:8 twist rate means a slug will complete a full rotation or spin once every 8 inches as it exits the barrel. Even now that we've covered what exactly barrel twist rate is, why does it matter? The spin boosts accuracy by improving the round's stability and aerodynamics as it leaves the barrel, therefore the more twists a bullet completes before leaving the barrel the more stable it will be. The lower the ratio of barrel twist rate the more spin the bullet will have, but longer and heavier bullets require a faster and tighter twist rate for the best performance from that ammunition - meaning better accuracy and range! Twist rates also lead into ammo selection which also references back into our recent article on grain count and why it matters (READ THAT ARTICLE HERE), Here is a handy chart from the NRA which gives a good virtual representation on grain count to barrel twist:

One thing we do want to make clear and as seen in the chart above, Twist rate and ammo selection does NOT affect the safety of your AR, Twist rate and understanding it will just help you optimize the efficiency of your AR and get the best accuracy and range out of it as possible.

Now as mentioned briefly above, What are the twist rates and what twist rate do you want? To put it simply I have a preference to 1:8 twist rate, that's what most of my AR’s have- because a 1:8 twist is the most median ratio for different grain counts in ammunition, or to word it differently, it plays the nicest in the sandbox with the most different grain counts. Not to say that a 1:7 or 1:9 twist rate wont work just as well for you, they are just a little more picky to get the most out of them (as seen by the bullet weight in an AR15 barrel photo seen below).

As you can see the most median of the barrel twist rates would be the 1:8, being the most versatile- giving you the most flexibility, effectively stabalizing projectiles up to 80 grains but not overstabilizing lighter rounds.The others do have their advantages as well. Now when it comes to barrel twist rates it can be a bit complicated which leads to some “theories'' or opinions which are not forged in fact and can spread false information, Such as over twisting a bullet could lead to it flying apart in mid air which technically isn't impossible but is highly unlikely. Your biggest concern with barrel twist with certain ammunition should be accuracy. For example, if you want a mil-spec rifle, the 1:7 barrel runs 223 ammo loaded with a 62 grain projectile like a dream. This rate of twist can also handle even heavier bullets (up to 85 grains). However, if you want to run lighter 50-grain ammo through such an aggressive twist, you’re going to notice a deterioration in accuracy.

At the end of the day twist rate is just one way to achieve better accuracy and in my opinion a key part in better understanding firearms and their shooting ability, especially in AR’s as they are heavily referenced in this article. That being said, understanding and utilizing the twist rate on your firearm is not a fix all solution but it can definitely help you finetune your shooting performance and take you to the next level!