Airgun Barrel Twist Rate – Does It Matter?

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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.

Midway-4551364.jpg


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.

What's Inside Your Airgun Barrel? First Borescope Results


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!

Airgun Barrel Twist Rate


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.

Airgun Barrel Twist Rate


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:

Min Projectile WeightMax Projectile WeightRatio Min To Max
.22 Cal Airguns11.75 Grains40 Grains3.4 X
.22 LR Firearms20 Grains60 Grains3.0 X
.223 Cal Firearms35 Grains112 Grains3.2 X

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…


The post Airgun Barrel Twist Rate – Does It Matter? appeared first on Hard Air Magazine.
 
@hameditor The column titles in your table seem a bit off. Can you shift them one space to the right?
Thanks for noticing this. Like all the Hard Air Magazine articles that are shown in the HAM Community, it was originally created and published at www.hardairmagazine.com. There the table displays correctly, as is shown in the following screenshot.

Screen Shot 2024-04-04 at 11.38.41 AM.png
So this must be something to do with the software that translates it into the Community system. I'll ask our webmaster to investigate...
 
Love em or hate em FX has been huge in pushing slugs to the front of many airgunners minds. I know the lighter slugs (say 21/23 gr) are supposed to work well in their 'regular pellet' barrels. The heavy slug barrels are needed for accurate results on the bigger slugs. My S510 shoots the lighter stuff decently as well but not enough to replace a good ol 18gr Jsb! My Ghost HP is laughable with slugs. It has been said it has a 1:30 twist rate, so makes sense. Shot a few out of it....one went left, one went high, one went low, I gave up at that point😅 I find even the manufacturers themselves rarely point out the twist rate of their air guns. Either they like to keep it hush hush, or they figure if the gun is accurate, the new owner doesn't care?! They mention speed, weight, etc but rarely twist rate. I don't care enough to know (apparently 🤣) what my TX, Slavia, or S510 twist rate is.
 
This topic has potential.🙂

Barrel twist variants have been around for years, even for pellets.

Look at the old Korean barrels, older German ones also. Many not the standard 1:17.7 twist.


FX and slug use simply made variations of twists more of marketing commodity. Previously it was something the manufacturer simply used to maximise their rifle performance.

By default I have 6 different barrel twist rates, ranging from a Haenel that is older than my wife up to a more recent RTI long range barrel. All dedicated pellet barrels.

Unwittingly I've been a barrel tester for so many years, just never expected the twist at the end.😉

Profit.
 
Twist rates are a subject I have carried out many individual studies on over the years. There are a number of posts on various forums, mostly though for 12FPE speeds and ranges up to 50 metres. At the speeds and ranges looked at, twist rates in the 16 to 22 inches per turn tend to come out best for the pellet shape used in both .22 and .177 sizes. At different speeds and ranges the values differ, the longer the range the slower the twist rate.

For slugs, the comparison thread on lead and lead free slugs contained information on twist rates, but it was for one basic design of slug with different lengths for the different weights. The twist rate needed for stability will depend on a lot more than length and weight. The external shape and the mass distribution will have first order effects on the twist rate needed. Higher speeds as they approach Mach 1 will also need higher twist rates, particularly for boat tailed slugs.

Stability is not the only factor to consider for twist rates, there is also group sizes. I have recently been looking at pellet twist rates for pellets with speeds from 800 to 1050 ft/sec at ranges up to 100 yards. There appears to be a range of golden values for the average stability factor at all speeds and ranges. A lot more study is needed for different pellet shapes and sizes, but at the moment the golden range of values seems to be surprisingly consistent.

I will report on what I have done when I can be a bit more sure the results so far are not a fluke. I can post the old 12FPE posts if they are of interest.
 
Love to learn! Ive been working on this myself but the biggest problem is the lack of available barrels in different twists and then finding a good machinist. Keep these types of articles coming so i can learn more!
 
View attachment 5519

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.

Midway-4551364.jpg


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.

What's Inside Your Airgun Barrel? First Borescope Results's Inside Your Airgun Barrel? First Borescope Results


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!

Airgun Barrel Twist Rate


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.

Airgun Barrel Twist Rate


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:

Min Projectile WeightMax Projectile WeightRatio Min To Max
.22 Cal Airguns11.75 Grains40 Grains3.4 X
.22 LR Firearms20 Grains60 Grains3.0 X
.223 Cal Firearms35 Grains112 Grains3.2 X

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…


The post Airgun Barrel Twist Rate – Does It Matter? appeared first on Hard Air Magazine.
I have a older Marlin .22,and it shoots almost every weight up to the 60gr. as well as I can hold it. There are few exceptions. The 60gr. hits hard,but very unstable upon contact with critters. Very few exits on groundhog size pests,great penatration in solids(wood). Twist rate is 1:16 with marlin's micro groove. I have shot silhouettes with the 60gr.,and the drop is comparable to a 45/70/500. Groups average around 1- 11/4 in. at 100 yards. Stock and trigger work done,but it shot great even before the work. I wish that I could get another brick of the Aguila 60gr.!!
 
I'm glad you brought up this subject, Mr. Archer. A high end air gun company *should* have twist rate info available on their whole line considering the cost involved. Also, some of us now have night vision optics that needs that information to set up the correct parameters for an accurate firing solution.
 
I have always stated to airgun makers the importance of twist rate. It would seem to be a common knowledge to them but for reasons we all know they want to ignore that. I not too long ago did away with a superior smooth twist barrel for a TJ barrel because the TJ barrel T.R. and quality is soo much better. I went with a 1:16 because I shoot heavy at longer ranges. If a air gun maker calls a model a "sniper" version then you'd think they'd include a sufficient barrel TR to support that claim. Bottom line, when you know things then you can make a better choice by asking the right questions.
 
I have always stated to airgun makers the importance of twist rate. It would seem to be a common knowledge to them but for reasons we all know they want to ignore that. I not too long ago did away with a superior smooth twist barrel for a TJ barrel because the TJ barrel T.R. and quality is soo much better. I went with a 1:16 because I shoot heavy at longer ranges. If a air gun maker calls a model a "sniper" version then you'd think they'd include a sufficient barrel TR to support that claim. Bottom line, when you know things then you can make a better choice by asking the right questions.
Did you order your barrel from tj finished for your gun or did you have to find a machinist?
 
Twist rates are a subject I have carried out many individual studies on over the years. There are a number of posts on various forums, mostly though for 12FPE speeds and ranges up to 50 metres. At the speeds and ranges looked at, twist rates in the 16 to 22 inches per turn tend to come out best for the pellet shape used in both .22 and .177 sizes. At different speeds and ranges the values differ, the longer the range the slower the twist rate.

For slugs, the comparison thread on lead and lead free slugs contained information on twist rates, but it was for one basic design of slug with different lengths for the different weights. The twist rate needed for stability will depend on a lot more than length and weight. The external shape and the mass distribution will have first order effects on the twist rate needed. Higher speeds as they approach Mach 1 will also need higher twist rates, particularly for boat tailed slugs.

Stability is not the only factor to consider for twist rates, there is also group sizes. I have recently been looking at pellet twist rates for pellets with speeds from 800 to 1050 ft/sec at ranges up to 100 yards. There appears to be a range of golden values for the average stability factor at all speeds and ranges. A lot more study is needed for different pellet shapes and sizes, but at the moment the golden range of values seems to be surprisingly consistent.

I will report on what I have done when I can be a bit more sure the results so far are not a fluke. I can post the old 12FPE posts if they are of interest.
Speed was something I thought on as well .. your not going pb speeds so ...???

But a bove spinach said about that 1-30 rate but for slugs that tend to fall under longer heavier .. I'd of thunk way tighter .. way.. my better guns in .177 or .22 pellets ate 1-17 or 1-24 averaging 850fps .. but that 1-30 twist ijdk...
 
I forgot to mention that the 60gr. Aguila were clocking in at 940- 950 fps from a 24 inch barrel. I know of another of the same make that won't shoot them at all. Go figure!
 
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This was a big thing to me back in the 80s when they first came out with sabots because at that time, I was really interested in the muzzle-loader deer season and wanted to shoot the sabots. The slow twist barrels like say a 1:72 or 1:66 were good for round balls, and faster twist barrels like 1:28 or 1:48 were good for slugs. At that time everything was pretty much 1:72 or 1:48 unless you bought a really high-end rifle. Now, they offer 11 different twist rates and smooth bore for muzzle-loaders that I am aware of. It really does make a big difference with the muzzle loaders and made a big impression on me at the time. I believe calibers and speeds also have a factor in choosing twist rates. The longer the bullet, the faster the twist rate needs to be to stabilize it. But slugs fired at a low speed will lead fowl a barrel fast. That is why most handgun rounds are copper jacket or hard cast, no one in their right mind would shoot pure lead in a PB handgun unless they want to turn it into a fishing weight. This is also one of the reasons why you see slug shooters powder coating their slugs. Another interesting thing to me is that if a rifle bullet is fired at too high of a speed, it can melt on the way to the target and just splatter it with lead.
 
Speed was something I thought on as well .. your not going pb speeds so ...???

But a bove spinach said about that 1-30 rate but for slugs that tend to fall under longer heavier .. I'd of thunk way tighter .. way.. my better guns in .177 or .22 pellets ate 1-17 or 1-24 averaging 850fps .. but that 1-30 twist ijdk...
The 1:30 barrel shoots pellets only. High speed pellets 😉.
It works well, not pellet fussy.

I've a .22 1:16 twist with a light choke. Works well with pellets and slugs. I've tried nothing above 30 grain though.
I prefer smooth shooting.

Both barrels mentioned above are RTI spec, LW barrels.
 

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