Barrel length vs accuracy

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Erik

Erik

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Aug 29, 2016
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Does a longer barrel give better accuracy?

I've been looking a lot at the Edgun Leshiy with 350mm barrel. That is shy of 13,8". And here are some other Short barreled guns:

Edgun Leshiy: 350mm - 13,8"
Edgun Lelya: 295mm - 11,6"
Mutant Short: 280mm - 11"

Does this make the Leshiy the Most accurate of the bunch??? Or how does it work?

I am talking about the guns accuracy here and not the shooter, so human error is ignored. Pretend it is in a vice if that helps.
 
Not necessarily. There are about 10 different factors which affect accuracy and barrel length is one of them. A good example is a stub nosed revolver. Obviously, they're not as accurate a say one with an 8 inch barrel. There is an upper limit too, but that is controlled by several of the other (unnamed) factors. The W.A.R. Warp has a rather short barrel (≈12 inches as I recall), and it is superbly accurate. 
 
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Longer barrel means more velocity.....not more accuracy. However, with velocity comes increased accuracy at longer ranges. This is a general rule of thumb. If the barrel is too long it can actually slow the projectile down.....but this is rare and shouldnt concern you. It really comes down to velocity. A short barrel shooting the same velocity as a longer barrel does have a disadvantage still......the escaping gas behind the pellet is at a much higher pressure and therefore there is more turbulance on the skirt of the pellet as it leaves the crown.
My advice......if shooting long range stick with a proven long range platform. If shooting shorter ranges you will probably never tell the difference.
 
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"Marksman3006"Longer barrel means more velocity.....not more accuracy. However, with velocity comes increased accuracy at longer ranges. This is a general rule of thumb. If the barrel is too long it can actually slow the projectile down.....but this is rare and shouldnt concern you. It really comes down to velocity. A short barrel shooting the same velocity as a longer barrel does have a disadvantage still......the escaping gas behind the pellet is at a much higher pressure and therefore there is more turbulance on the skirt of the pellet as it leaves the crown.
My advice......if shooting long range stick with a proven long range platform. If shooting shorter ranges you will probably never tell the difference.
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Unfortunately, I can't agree with everything you say.
A long barrel can indeed slow a pellet down, but this counts mostly for springers.
Pcp's in general will generate more speed with a longer barrel, at least, with the barrel lenghts found on "regular pcp's"
A shorter barrel is also more rigid than a long one, if the diameters are the same. This can be good for accuracy (less critical barrel harmonics)
If a barrel crown is cut perfectly symmetrical (I always cut 11° target crowns on my blanks), the turbulence you are talking about will also be symmetrical.
Otherwise, powderburners couldn't be that accurate, because the pressure at the muzzle of a PB is way, WAY higher than the muzzle pressure of a pcp airgun.

Actually it is pretty simple, a pellet needs a certain rotation and speed to fly stable.
If this is achieved with a short or long barrel doesn't matter.
The downside of a short barrel is the higher air consumption compared to a long barrel, but this can be partially compensated for by running a higher regulator pressure.
A short, intense pulse of air propels the pellet with a higher acceleration in the first part of the barrel, resulting in less air waste, and a more quiet muzzle report.

Regards, Gijs

 
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"but this can be partially compensated for by running a higher regulator pressure.
A short, intense pulse of air propels the pellet with a higher acceleration in the first part of the barrel, resulting in less air waste, and a more quiet muzzle report."

That was interesting, it would be great to have the same fpe on the shorter barrel without loosing too much air because of it.
 
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"Erik"Does a longer barrel give better accuracy?

I've been looking a lot at the Edgun Leshiy with 350mm barrel. That is shy of 13,8". And here are some other Short barreled guns:

Edgun Leshiy: 350mm - 13,8"
Edgun Lelya: 295mm - 11,6"
Mutant Short: 280mm - 11"

Does this make the Leshiy the Most accurate of the bunch??? Or how does it work?

I am talking about the guns accuracy here and not the shooter, so human error is ignored. Pretend it is in a vice if that helps.
Click to expand...

My Shorty barrel is around 13". Is yours 11"?

On the question about accuracy, I think a longer barrel does improve accuracy if all else is equal. It's not easy to prove one way or the other because all else is never equal. Even if you use two different length barrels in the same gun, no two barrels are equal. Plus the extra weight of the longer barrel helps with stability. 

I'm basing my opinion (and it's only an opinion) on the fact that, for every gun I can think of that is available with multiple barrel lengths, the longer one is always more accurate and I don't think it's just the power. 

Also, there are no pistols that are more accurate (or even comparably accurate) to rifles made by the same company. 

If you're talking about a difference of only 2", I doubt the difference would be enough to matter. If you look at rifles made for long range accuracy, they almost always seem to have longer barrels. 



 
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Here is a thought: No extreme bench rest competitor or Olympian shoot has ever won a competition with a short barrel PCP airgun. Now with that being said length is all about comparison, 3 yards vs 5 yards, 10 inches vs 15 inches, or 6 meters vs 9 meters it all depends on what you are comparing something too. In general at longer barrel should perform as good as if not better than a short barrel, but haven't every seen or read the opposite. SAME as or BETTER.
 
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Most if not all the studies on this topic seem to be for powder burners. There is a number people who claim to have run studies that prove that length makes no difference for powder burners. They have results from their tests to support their claims (albeit with limited sample sizes). For some reason, nobody is listening because long range target guns are still not being sold with pistol barrels. Why?

There is the power thing but powder burners produce significantly more energy than air guns and adjusting the load has less of an impact on usability than increasing air usage, so they could easily compensate for shorter barrels.

It it is also worth noting that the most accurate air guns are rarely the most powerful ones at competition shooting distances. If anything, high price precision air rifles are tuned down to shoot at fairly modest speeds, so they are not relying on barrel length just for power.

Either way, I wouldn't be using barrel length to choose an air gun or grade their accuracy. It means nothing on it's own. 

Edgun seems to recommend the Morona rifle for long range accuracy. This also happens to be a long rifle. I doubt they'll be recommending their pistol for long range competition any time soon. It's for short range hunting while backpacking apparently. 




 
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This discussion could go a variety of ways, as there is both good and bad information presented here. 

No matter the means of propulsion, there is a penultimate length. That length depends on the caliber, weight of the bullet or pellet, the force behind it (air or gun powder), twist rate, and even the ballistic coefficient of the projectile. And I should add, about a dozen other variables. 

We also must take into consideration the difference between bullet and pellet. Bullets are spin stabilized, and pellets are both spin and drag stabilized. And airguns may shoot one, the other, and perhaps both further muddying the waters. 

The bottom line is, length matters, but it is only one single, perhaps fixed, variable, not the whole gambit!
 
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"zebra"Most if not all the studies on this topic seem to be for powder burners. There is a number people who claim to have run studies that prove that length makes no difference for powder burners. They have results from their tests to support their claims (albeit with limited sample sizes). For some reason, nobody is listening because long range target guns are still not being sold with pistol barrels. Why?

There is the power thing but powder burners produce significantly more energy than air guns and adjusting the load has less of an impact on usability than increasing air usage, so they could easily compensate for shorter barrels.

It it is also worth noting that the most accurate air guns are rarely the most powerful ones at competition shooting distances. If anything, high price precision air rifles are tuned down to shoot at fairly modest speeds, so they are not relying on barrel length just for power.

Either way, I wouldn't be using barrel length to choose an air gun or grade their accuracy. It means nothing on it's own. 

Edgun seems to recommend the Morona rifle for long range accuracy. This also happens to be a long rifle. I doubt they'll be recommending their pistol for long range competition any time soon. It's for short range hunting while backpacking apparently. 




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Length DOES matter in powderburners (and pcp's), but mostly to gain speed and efficiency.
That's also the reason for longer barrels, the pistol story you brought up is apples to oranges if you ask me. The pistol barrel just can't give the desired speed. But it certainly can be dead accurate, at the cost of speed.
I'd rather have a shorter heavy barrel when looking for accuracy than a long skinny one.
Keep in mind barrel behaviour of PB's and pcp's is comparable in a lot of ways.
 
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I'm not saying I know for sure one way or another. In fact, I definitely don't and haven't seen anything I would consider conclusive. 

My opinion is only based on what I see and the limited experience I've had of using the same air rifle with different length barrels. It could easily be changed. 

I have yet to see an air pistol match the accuracy of an air rifle of comparable quality, even if they set to output identical power. It is definitely possible for air pistols to output 20fpe and, as far as I know, people still aren't using them to compete in BR or FT successfully against rifles. It clearly isn't a power limitation as pistols are capable of hitting the max power allowed for matches.

I have a 25 cal Career 707 rifle and the carbine. Even if I set them up to fire the same projectile at the same speed, the rifle has the edge in accuracy beyond 50yards. A Marauder pistol does not do as well as the rifle beyond 30 yards. I think that would apply even if the rifle was tuned down to match the pistols power. 

I know there are a few people here who own both the mutant shorty and the standard. I would be interested to know their thoughts on comparative accuracy. They could be power matched fairly easily. I would consider that to be a good test because of how solid the platform is. I think it will minimize other variables. 

It might be something as simple as the extra weight of a longer barrel providing more stability upfront. 

Has there ever been a test on the effect of barrel length on airgun accuracy? I can think of a number of reasons why the results might differ from powder burners. 


 
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Every projectile has an optimum velocity and spin rate if it can exit the barrel
at the valley or the crest of the barrels harmonic wave. That's as good as it gets.
Length of the barrel became much less an issue back when rifling was invented.
Short or thicker ( bull) barrels have a smaller wave than a thin long one. But if the
velocity and spin rate are correct and the projectile exits the barrel at the valley or
peak of the wave a thin whippy barrel will out shoot any and all that don't.
Of course billions and billions of other factors play a part as well. But if you can
get velocity spin and harmonics to play together nicely you will have accuracy
or precision regardless of barrel length.
Harmonics play a smaller part in pcp guns that's one reason why they are so easy to
shoot. Its also the reason springer's are harder to be as accurate with. Long is easier
to aim than short but not necessarily any more precise.
 
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"Alan"Not necessarily. There are about 10 different factors which affect accuracy and barrel length is one of them. A good example is a stub nosed revolver. Obviously, they're not as accurate a say one with an 8 inch barrel. There is an upper limit too, but that is controlled by several of the other (unnamed) factors. The W.A.R. Warp has a rather short barrel (≈12 inches as I recall), and it is superbly accurate.
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The barrel length on the snub nose revolver isnt the culprit for reduced accuracy compared to the longer barrel. The shorter sight radius of the shorter barrel is the cause. 

 
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It is a Balance of everything that improves accuracy
  • Twist rate of rifling
  • length of barrel
  • weight and type of round being shot
  • power (be it powder or air) that is being applied to the round
Fact is To much power behind a round can cause it to start tumbling, and or break the sound barrier A longer barrel can help balance that power especially when the air gun has a regulator to even out the power curve.
The rate of twist of a rifle will play a big role in choosing what rounds will shoot best out of that barrel so the rate of twist is relevant to the length of said barrel
The one very big difference between air rifles and powder burners is "Cold Bore", Because Air Rifles are shooting cold bore with every shot they do not need to worry about heat expansion, The only issue that they need to be concerned with is barrel harmonics (This is especially true in springer's) because of the relative slow speed of the round compared to powder burners a cheap Un-Tuned barrel will be doing the shimmy shimmy shake before the round is out on it merry way to punch a hole in something. The primary reason break barrels are longer is so you do not have to be heman to cock the things. More expensive springers and barrels will be adjusted in length to offer the best harmonics matched to the power plant behind it.
I will say this about cold bore shooting, leave a long barreled rifle out in the sun and see what happens to your zero (Long Distance Shooting) 
Tuning and balancing is the key to good accuracy in an air rifle, not necessarily the just the length of the barrel. 
A properly tuned airgun with a short barrel will outshoot an untuned long barrel or vise versa 
naturally that statement does caveat quality 


 
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"Alan"Not necessarily. There are about 10 different factors which affect accuracy and barrel length is one of them. A good example is a stub nosed revolver. Obviously, they're not as accurate a say one with an 8 inch barrel. There is an upper limit too, but that is controlled by several of the other (unnamed) factors. The W.A.R. Warp has a rather short barrel (≈12 inches as I recall), and it is superbly accurate.
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The barrel length on the snub nose revolver isnt the culprit for reduced accuracy compared to the longer barrel. The shorter sight radius of the shorter barrel is the cause.
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sight radius has nothing to do with physics. the short barrel of the revolver makes it prone to muzzle rise from recoil. longer barrel revolver will be more accurate than a snub nose revolver because of the heavier longer barrel negating muzzle rise and recoil. I'm not an expert in rifle physics, its common knowledge from shooting different firearms.
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