What does barrell length have to do with accuracy
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Arkansas Paul
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I think it has more to do with a longer sight picture than barrel length when speaking of handguns. It isn't necessarily the length of the barrel but the sights are easier.
celem
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I'm sure that there are a variety of reasons, however one obvious reason is that the further apart the front and rear sights are the less impact there will be from minor alignment errors. This is a major reason why rifles are more accurate than pistols.
The_Next_Generation
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In addition to a longer sight-picture and less muzzle-flip, a longer barrel will theoretically better stabilize a bullet than a short one. However, I would think that if a barrel was too long (in the extreme) that the lag time from trigger-break to the bullet actually leaving the muzzle may be a cause for inaccuracy as a result of shooter-error (like flinching).
SFsc616171
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1. A longer barrel does give you a better sight radius, i.e., the distance from rear sight to front sight, as viewed when a Smith and Wesson Model 442 snubnose revolver is laid next to a Smith and Wesson M and p Victory model revolver, 1.785 barrel to a 5-inch barrel.
2. Every semi-auto manufacturer has their own stats for a given model and barrel length, as to accuracy at said distance, with said ammunition. For example, the FN original spec for the Browning Hi Power, at 50 meters, with a 124 grain projectile, were to have a target grouping that would fit inside a coffee mug! The same thing goes with revolvers, i.e., S and W .38 Specials are 'standardized', and zeroed, for use with a 158 grain projectile.
2. Every semi-auto manufacturer has their own stats for a given model and barrel length, as to accuracy at said distance, with said ammunition. For example, the FN original spec for the Browning Hi Power, at 50 meters, with a 124 grain projectile, were to have a target grouping that would fit inside a coffee mug! The same thing goes with revolvers, i.e., S and W .38 Specials are 'standardized', and zeroed, for use with a 158 grain projectile.
The_Next_Generation
Member
MistWolf, I disagree. There have been several studies conducted investigating the effect of barrel-droop as a result of a long barrel. Shorter barrels will be stiffer and therefore more accurate than a longer barrel of the same thickness. I think the someone like the FBI concluded that 18" or so was optimal for the 308 accuracy-wise, but I'm not sure where the article went.
Here is an article on TTAG. Ignore what they wrote as their posted data reveals the 16" and 18" barrels to be slightly more accurate than the 26" barrel. I know a few tenths of an inch is negligible, but an increase is an increase: http://www.thetruthaboutguns.com/20...t-barrel-length-muzzle-velocity-and-accuracy/
This would only be true in very limited circumstances. If, for some reason, a particular rifling twist was very marginal in terms of stabilizing a bullet, a longer barrel would probably increase muzzle velocity and since increasing muzzle velocity increases the bullet spin for a given rifling twist, the longer barrel might stabilize a bullet that a short one wouldn't.
In a pistol, if this were to happen, it would be an obvious case of having the wrong rifling twist--a fairly major error by the manufacturer--as opposed to being a benefit of having a longer barrel.
In a rifle, there's some potential for this kind of thing to occur if someone is experimenting with very heavy/long for caliber bullets.
Theoretically, yes. In practice, there are other contributors to accuracy that could certainly result in a long barrel being more accurate than a shorter one of equal thickness.
Here's an example. This is a plot made by progressively shortening a barrel and shooting groups with it at each length. If you want to read about the test, here's the link.
http://www.accuratereloading.com/223sb.html
It's pretty easy to see that length did have an effect on the group size, but it certainly wasn't true that the gun shot with increasing accuracy as the barrel got shorter. In fact, the worst accuracy was at the shortest length--the second worse at the longest length.
Droop is the result of flex over length but it's the result of rigidity, not length. Increase the rigidity of the barrel, there will be less droop and less flex. Barrels can also be tuned in such a way that the flex is consistent to improve accuracy or even deadened.
There is a guy on a benchrest forum that experiments with barrel deadening. Use muzzle weights, he's tuned 22 rimfire barrels so they are accurate with many brands of ammo, not just a few. Two vibrations of certain frequencies will cancel each other out when they meet.
The barrel of the M1 Abrams is long enough that it has droop. Part of the ballistic calculations the firing computer makes is to account for that droop. I have a close friend that was part of the ground war in Desert Storm. He saw the Bradley that was killed by friendly fire from an Abrams tank. The Bradley was hit by two rounds at a pretty long range. The entry holes were close enough to touch. That's pretty accurate.
Shorter barrels are stiffer than their longer counterparts of the same diameter and generally shoot more consistently. The early pioneers of handrifles found they were getting amazing consistency form barrel lengths between 12 to 14 inches long. Every now and then though, they'd come across one that couldn't hit the broad side of a barn from the inside. They figured it was because the barrel harmonics were so screwed up.
Longer barrels of the same diameter have more flex. However, it's been proven time and time again that they will shoot when the right load gets it to vibrating just right. Or when tuned with a muzzle weight. The reality is, barrel quality plays a larger role in the accuracy of a barrel than length or profile. And while the flex of a barrel adds up with every inch of length, it's the vibrations and flex that has a negative impact on accuracy, not the length itself
LET ME ADD- My connection is slow tonight and I cannot get the charts to load on the article. But the author concludes
Good article. Thanks for the link
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M2 Carbine
member
I figure if this Micro Desert Eagle had about a half inch longer barrel it would be a lot more accurate because two shots passed just under the target. 
52 yards. Standing. Two hands.
As has been said, the longer barrel allows the shooter to see and hold a more precise sight picture, but within reason, the longer barrel doesn't mean more accuracy.
52 yards. Standing. Two hands.
As has been said, the longer barrel allows the shooter to see and hold a more precise sight picture, but within reason, the longer barrel doesn't mean more accuracy.
MistWolf's post is great, as is JohnKSa's. Assuming the bullet is rotating sufficiently to be stabilized, additional barrel length does not add mechanical accuracy, and may even slightly detract (mostly theoretical). It will add velocity, which will flatten trajectory, which makes getting hits easier at long distance (and, if the bullet starts supersonic, delay the transonic transition which does impact accuracy). For a gun with iron sights, it will generally add sight radius, which increases the precision of the sights. And it may reduce sway/wobble by adding weight.
So if by "accuracy," you mean the ability of the firearm, if held in PRECISELY the same position and fired in PRECISELY the same manner, to have bullets impact in the same spot repeatably, then, no, additional barrel length generally doesn't aid accuracy. If you instead mean that ability to hit what you wish to hit, then, yes, it may add some.
Check out some of the youtube videos of Bob Munden shooting targets at 200+ yards with a snubnose revolver if you don't believe it.
So if by "accuracy," you mean the ability of the firearm, if held in PRECISELY the same position and fired in PRECISELY the same manner, to have bullets impact in the same spot repeatably, then, no, additional barrel length generally doesn't aid accuracy. If you instead mean that ability to hit what you wish to hit, then, yes, it may add some.
Check out some of the youtube videos of Bob Munden shooting targets at 200+ yards with a snubnose revolver if you don't believe it.
A longer barrel will give the bullet more push from the powder charge at least up to a point. That gives you more bullet speed which means less drop and less problems from the wind. But of course that's just one of many things that go into the equation of how long a barrel should be.
Different calibers vary in how long is best. A 16" barrel is thought of as the minimum for a .22 to get top accuracy. The powder burns up before the bullet clears that 16". Larger calibers require more length.
I'm sure gun companies have tested their products to see what barrel lengths work best. I'm not sure what all goes into it. I know what people say. The bullet is kept going the right direction longer. There is better spin from a longer barrel. Better sight radius but of course not on a rifle with a scope. Less barrel flex with different lengths. Look at the tuners used on rimfire rifles to control barrel whip. That can affect any rifle and the harmonics of different lengths makes a difference on how much flex there is.
It's a complicated subject. It calls for some serious research IMO. I think most of us novices (when it comes to gun making) can learn from the people who make barrels and from the end results of the real world shooting of guns with different barrel lengths.
I do know that sometimes shorter is better. My Savage 12 LRPV has a 26" barrel. The action is the same as the Savage target guns but the barrel is 4" shorter. People who shoot Savages a lot claim the shorter barrel is actually better because the gun is more balanced. I can't verify that but I've heard it many times.
Different calibers vary in how long is best. A 16" barrel is thought of as the minimum for a .22 to get top accuracy. The powder burns up before the bullet clears that 16". Larger calibers require more length.
I'm sure gun companies have tested their products to see what barrel lengths work best. I'm not sure what all goes into it. I know what people say. The bullet is kept going the right direction longer. There is better spin from a longer barrel. Better sight radius but of course not on a rifle with a scope. Less barrel flex with different lengths. Look at the tuners used on rimfire rifles to control barrel whip. That can affect any rifle and the harmonics of different lengths makes a difference on how much flex there is.
It's a complicated subject. It calls for some serious research IMO. I think most of us novices (when it comes to gun making) can learn from the people who make barrels and from the end results of the real world shooting of guns with different barrel lengths.
I do know that sometimes shorter is better. My Savage 12 LRPV has a 26" barrel. The action is the same as the Savage target guns but the barrel is 4" shorter. People who shoot Savages a lot claim the shorter barrel is actually better because the gun is more balanced. I can't verify that but I've heard it many times.
Schwing
Member
I can tell you from the viewpoint of someone who is cross dominant that barrel length makes a huge difference in accuracy (I am speaking of sight alignment, not mechanical accuracy).
I cannot shoot with my right eye unless it is a rifle. I am sure there is someone in the know who can explain this but I shoot about 3 feet to the right at 15 yards with a pistol if I use my right eye yet I can hit dead center at 50-100 yards with almost any rifle (Iron sights). I have never been able to explain this since most cross dominant folks seem to have problems with rifles as well.
I cannot shoot with my right eye unless it is a rifle. I am sure there is someone in the know who can explain this but I shoot about 3 feet to the right at 15 yards with a pistol if I use my right eye yet I can hit dead center at 50-100 yards with almost any rifle (Iron sights). I have never been able to explain this since most cross dominant folks seem to have problems with rifles as well.
Barrel length does affect accuracy - by it's tuned length when fired. A barrel resonates when the powder charge goes off, gunmakers for years attempt to tune the frequency so the the muzzle is at a low node to reduce the group. It's better to have the muzzle exit not moving rather than moving at it's maximum travel - that spreads the group.
That's the reason the FBI showed that 18" was a good length for the .308 - the powder charges and bullet weights generally had most of the vibration at the muzzle at it's minimum, therefore, it was more accurate. The level of accuracy needed is another story - most hunting and combat firearms only need 2 MOA, which is about ten inches at 500 yards. The average human or deer has an 18" center of mass strike zone, ten inches is more than sufficient to put a bullet effectively into that area.
That's the conundrum - shooters like to compete and claim who is more accurate, the reality is that it doesn't take much to be effective.
That's the reason the FBI showed that 18" was a good length for the .308 - the powder charges and bullet weights generally had most of the vibration at the muzzle at it's minimum, therefore, it was more accurate. The level of accuracy needed is another story - most hunting and combat firearms only need 2 MOA, which is about ten inches at 500 yards. The average human or deer has an 18" center of mass strike zone, ten inches is more than sufficient to put a bullet effectively into that area.
That's the conundrum - shooters like to compete and claim who is more accurate, the reality is that it doesn't take much to be effective.
jamesjames
Member
The OP was interested in target or carry pistols. So discussions of barrel length out to 24 inches seems outside of the intended discussion.
Sure, there are specific barrel lengths and their intended uses:
6-8 inches are for target work and hunting in handguns (tight groups under 10 yards and accurate out to 100 yards)
5 inch barrels are combat pistols (1911, M-9) Combat distances out to 30 yards
4 inch barrels are duty pistols (LEO engagement distances out to 20 yards)
3 inch barrels are compacts and "kit guns" for hiking
2 inch barrels are for concealed carry (effective accurate range under 10 yards)
Every barrel length is a carefully considered niche in the market and functionality of sight radius and barrel length combined to offer accurate performance. IMHO.
Sure, there are specific barrel lengths and their intended uses:
6-8 inches are for target work and hunting in handguns (tight groups under 10 yards and accurate out to 100 yards)
5 inch barrels are combat pistols (1911, M-9) Combat distances out to 30 yards
4 inch barrels are duty pistols (LEO engagement distances out to 20 yards)
3 inch barrels are compacts and "kit guns" for hiking
2 inch barrels are for concealed carry (effective accurate range under 10 yards)
Every barrel length is a carefully considered niche in the market and functionality of sight radius and barrel length combined to offer accurate performance. IMHO.
Queen_of_Thunder
member
Thats how I see it. The closer to the target the better even if its only an inch.Longer barrel = Closer to the target
We were using the longer barrel lengths to discuss theory.
Your assessment of effective range for handgun barrel lengths is flawed. It doesn't take into account caliber performance or shooter's ability.
Sight radius does not affect mechanical accuracy. A longer sight radius does aid the eye to make a more precise aligment but is slower and requires finer motions to align. There Ain't No Such Thing As A Free Lunch.
Bottom line is, there is no difference in mechanical accuracy between a 2 inch and 4 inch barrel. The difference in sight radius is a small trade off between precision & speed
I would add that the shorter the barrel, the shorter the grip, and that influences accuracy to a great degree in a pistol.
That a heavier barrel will have less resonance might be a given, adding a muzzle weight to dampen it was a factory option on Brownings and frequently done on target rifles. Moving it around is a lot better tuning it than cutting barrels down to some nominally effective length and recrowning.
As for pistols needing to reach out beyond 21 feet, the dynamic of combat pretty much dictate you should be using a rifle long before that distance is narrowed so closely. Since it's a pistol conversation, the average one is accurate enough. It's the shooter who isn't.
In that regard, I obtained my CCW with a Glock 19C and kept most of them in the 8 ring at 21 feet with 2 hours sleep. Test firing my new LCP, I was lucky to keep them on a large black target at 25 yards. I really don't think the barrel length had much to do with it, the grip length makes a difference in keeping the barrel pointed down range.
So I sold the LCP and now shoot a P938 with finger rest. Much better grip, steadier hold, more accurate. We tend to cut the grip down a lot for CCW but maybe we have gone a bit too far and need to pull back a tad. The NRA has a CCW shooting course with barrel length limits, I bet the better shooters are using the longest grips they can get away with.
In fact, I'm going to predict that as a trend of the future.
That a heavier barrel will have less resonance might be a given, adding a muzzle weight to dampen it was a factory option on Brownings and frequently done on target rifles. Moving it around is a lot better tuning it than cutting barrels down to some nominally effective length and recrowning.
As for pistols needing to reach out beyond 21 feet, the dynamic of combat pretty much dictate you should be using a rifle long before that distance is narrowed so closely. Since it's a pistol conversation, the average one is accurate enough. It's the shooter who isn't.
In that regard, I obtained my CCW with a Glock 19C and kept most of them in the 8 ring at 21 feet with 2 hours sleep. Test firing my new LCP, I was lucky to keep them on a large black target at 25 yards. I really don't think the barrel length had much to do with it, the grip length makes a difference in keeping the barrel pointed down range.
So I sold the LCP and now shoot a P938 with finger rest. Much better grip, steadier hold, more accurate. We tend to cut the grip down a lot for CCW but maybe we have gone a bit too far and need to pull back a tad. The NRA has a CCW shooting course with barrel length limits, I bet the better shooters are using the longest grips they can get away with.
In fact, I'm going to predict that as a trend of the future.
jamesjames
Member
sure, there's no difference in mechanical accuracy in a 2 inch or a 4 inch barrel clamped into a shooting rest.
I still believe the OP was looking for more real world performance in his question.
Yes, grip length is a factor to consider. Isn't it interesting that grip length, barrel length, and sight radius are all correlated. Hmmmm... how might that affect accuracy and performance firing off hand?
You can have esoteric discussions of droop, barrel harmonics, and caliber all you want. The OP was asking about barrel length in handguns. so maybe I'm not so far off after all.
I still believe the OP was looking for more real world performance in his question.
Yes, grip length is a factor to consider. Isn't it interesting that grip length, barrel length, and sight radius are all correlated. Hmmmm... how might that affect accuracy and performance firing off hand?
You can have esoteric discussions of droop, barrel harmonics, and caliber all you want. The OP was asking about barrel length in handguns. so maybe I'm not so far off after all.
Barrel length has nothing to do with mechanical accuracy, especially in a pistol. What a longer barrel provides is a longer sight radius which helps the shooter line up on the target. This assumes that regardless of the barrel length that it is a quality barrel. Most decently constructed pistols are more accurate than the shooter is.
Queen_of_Thunder
member
Seems to me that a longer barrel provides for a complete burning of the powder with a full transfer of energy to the bullet and stablization of said bullet.
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