Airgun Barrel Twist Rate – Does It Matter?

Now I have not shot firearms in many years. However, I remember that barrel twist rate always seemed to be a big deal in the powder-burning world.

Recently I was reminded of that when browsing the Midway USA website. Take a look at the product description pages for just about any firearm and there – among the key product specifications – is barrel twist rate.

Looking further, I find much Internet information and discussion about twist rates, particularly for AR 15-type “black rifles”.

What interests me about this is that relatively small differences in twist rate – say 1 in 7 or 1 in 9 (Inches) are attributed with considerably different levels of accuracy downrange, depending on the bullet weight.

Moreover, the results of these differences in twist rate seem to be significant even though the bullet weights and basic shapes of the projectiles look RELATIVELY similar – at least to me.

Now it’s important to understand that I am MOST DEFINITELY NOT A BALLISTICIAN. (My above comments undoubtedly prove that statement to be true!)

However, my understanding is that – at least in the powder-burning world – longer and/or heavier bullets benefit from a faster twist rate. That led me to start thinking about airguns…

What Is Barrel Twist Rate?

Rifled barrel have a series of “lands and grooves” cut into the bore. We looked at them recently in this Hard Air Magazine post.

In fact, these lands and grooves are not parallel to the direction of the bore, they are cut in a slow spiral. In other words, they are “twisted”.

Thus the twist rate is the length along the barrel taken for the bullet, pellet or slug to make one 360 degree rotation as it passes down the barrel. It’s expressed in Inches: for example a “16-Inch twist rate” tells that there’s one rotation for every 16 Inches traveled down the barrel. It’s usually written 1:16.

Does Airgun Barrel Twist Rate Matter?

Generally, I find very little discussion of airgun barrel twist rates. It’s often not easy at all to find out the twist rate for the barrel of the air rifle you’re planning to buy, or even of the one you have.

Yet this is starting to change, a little!

The appearance of slugs has raised interest in airgun barrel twist rates, with them being different for “slug barrels”, for example.

At the 2024 IWA OutdoorClassics show recently, twist rates were quoted for some air rifles. This was particularly marked in the case of Eastern European brands, I noticed.

Still, I am surprised that there is not more interest in this topic among airgunners. After all, the range of profiles and weights for airgun ammo has increased dramatically in recent years and continues to do so.

Airgun Ammo Variability

Compared to firearms, airgun ammo has some vary major differences. There’s the huge difference between waisted, “Diabolo” pellets and parallel-sided slugs, for example. Then there’s major differences between head profiles – from flat-fronted wadcutters through domes to pointed pellets, hollow points and everything in between.

Plus, the weight differences are extreme, too.

To focus our discussion a little, let’s concentrate on .22 caliber for two reasons. There’s a huge variety of ammo available, plus we can make a few comparisons to .22 firearm calibers also.

The “traditional” average weight from .22 caliber lead pellets has been in the 14 – 15 Grain range. Think 14.3 Grain Crosman Premiers, for example. However, the lightest .22 caliber lead-free pellets (Predator GTOs) come-in at just 11.75 Grains.

Now to the other extreme. The heaviest .22 caliber lead pellet I am aware of is the 33.96 Grain JSB Jumbo Beast.

Moving to slugs, the heaviest normal production slugs I know weigh 40 Grains. These are the H&N Slug HP heavies, although others have matched that weight, too.

Making a very simple comparison between ammo weights, we see:

As we see, .22 caliber airgun ammo is at least as variable in weight as .22 LR and .223 caliber powder-burning ammo. PLUS, there’s the huge differences in shape, too, that’s not present in firearms bullets to anything like the same extent.

Yes, I know there’s significant velocity differences between the three types, but I’m putting that on one side for this discussion.

Anyhow, I would have thought that – as barrel twist rate is a significant issue for .22 LR and .223 firearms, they ought to be for .22 caliber airguns as well. And – by extension – for other airgun calibers also.

We’ll explore this topic further in another HAM post…

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