How much accuracy is gained by an inch of barrel?

For the most part, mechanical accuracy isn't a function of barrel length.

I'd say the accuracy would be better because of the longer sight radius rather than another inch of barrel.

giggitygiggity said:

I'd say the accuracy would be better because of the longer sight radius rather than another inch of barrel.

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^^^ This.

How much accuracy is gained by an inch of barrel?

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Quick answer -- none. Accuracy has nothing to do with barrel length.

In practice, however, sight radius is a key factor in accurate aiming. A handgun with a long sight radius will be easier to shoot accurately than one with a very short sight radius.

In Elmer Kieth's famous use of Harold Croft's highly-modified Colt SAAs, he hit a 4X4 foot target at 700 yards with all four guns. With the 2 1/2" barrel gun, it took him 12 shots to get on target. With the 7 1/2" barrel gun, he hit it five out of six shots.

In Elmer Kieth's famous use of Harold Croft's highly-modified Colt SAAs, he hit a 4X4 foot target at 700 yards with all four guns. With the 2 1/2" barrel gun, it took him 12 shots to get on target. With the 7 1/2" barrel gun, he hit it five out of six shots.

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That pretty well proves that a longer sighting radius is more accuates. The 2 1/2" gun hit the target only 8% of the time while the 7 1/2 gun hit 83% of the time.

We all know the barrel length does not effect mechanical accuracy, but because of the longer sighting radius it is an aid in aiming. In effect, yes longer barrels are going to produce more accuracy when shot with iron sights. With optics, there would be no difference.

Exactly how much is hard to say, but everything else being equal 1 more inch of barrel length (sighting radius) will be more accurate. Things are not always equal though. Some guns are simply more accurate than others even with equal length barrels (sighting radius). It would be entirely possible for me to shoot a 3" gun to shoot more accurately than a 4" gun if the shorter gun is mechanically more accurate.

In some instances, a shorter barrel even ends up being more accurate due to barrel harmonics, flaws in the steel, and, in general, less flex from a shorter barrel.

I'd say the accuracy would be better because of the longer sight radius rather than another inch of barrel.

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Accuracy is one thing -- it's pretty much a mechanical thing. Shootability (and the ability to shoot the gun to it's fullest potential) is another. (And with long guns, other factors come into play -- as noted above.)

A longer barrel doesn't make a gun more accurate. It does help increase the performance of a given round - the speed with which it leaves the barrel...

A longer sight radius can make the gun easier to shoot well, but that's a gun/person interface thing, and not a function of the gun's innate accuracy. It's sort of like good triggers: they don't make the gun more accurate, but help the shooter take advantage of what's there more easily.

Put the gun in a Ransom Rest and test it, and you'll find it's accuracy. Put the same gun with a longer barrel in the Rest and test it, and you'll not likely see much difference if all other things are essentially the same.

A shooter MIGHT find the longer-barreled gun easier to shoot (i.e., easier to hit the target) -- but a good shooter with good eyes might not care that much, one way or another.

I would agree with this.

If I really concentrate, I can shoot my 2.5" detective special as well as I can shoot my 8 3/8" Pre-27.

It is just easier to shoot the 8 3/8" pre-27 more accurately. The key is ease.

The guns are truly equal accuracy I believe.

I think we all can agree the inherent accuracy of a pistol is not a function of barrel length.

But sight radius matters if you are using irons.

I can keep all of my shots on a 12" gong target at 25 yards with a 38 Spl Detective Special with a 2" barrel. I shoot standing, not off a bench. I do not have the same hit probability at 50 yards with the same target, I am doing well to hit the target one to two times out of six shots. With a 4" Colt Police Positive, the same action with a 4" barrel, I have to work at it, but I keep all six rounds on target at 50 yards.

I have experimented with 3" barrels, 5" barrels, and 7.5 inch barrels. My hit probability goes up with 3" barrels compared to 2", 5" barrels are slightly better at 50 yards than a 4". The 7.5" barreled pistols have a high hit probability all the way out to 100 yards.

I think a 5" barrel is the best all around for open carry, but sometimes you just have to make do with smaller concealed carry sidearms.

sight radius makes the difference. I switched from a 4" barrel G23 to a 3" barrel XDsc a few years ago in my HD pistol and noted a significant decrease in accuracy. i don't think it had anything to do with the manufacturing, but rather the decreased sight radius.

Yes, longer sight radius can lead to more accurate shooting but another factor is barrel time on low velocity pistol rounds. Longer barrel=longer barrel time=more time for wiggle. Back when Bullseye shooting was the only game in town, the 5" 22's, Smith 41's or Hi-Standards, could be shot more accurately than the 7" models, all other factors being equal.

I've actually noticed the opposite effect with regards to my 1911 shooting. I used to own a 5" SA 1911A1 and a 5" Ruger 1911, and I shot them about equally well. I went and bought a Commander length (4.2") Sig Scorpion and I shoot it better than any handgun, period. Better than my 5.5" Ruger MkII Target actually (which still baffles me!).

Granted, it would be better if I was comparing a Sig to a Sig here, but I do all of my shooting offhand and I doubt the 1.5" group shrinkage at 25 yards is due to mechanical accuracy differences. I have noticed that the front sight on the 4.2" gun seem to fit more "tightly" in the rear notch and so it becomes easier to center naturally. This may be what is coming into play here, also perhaps the cool tan color and neat grips

i have to figure you all are correct, being more experienced than myself, but if it makes a round shoot straighter and helps you aim better, i guess it does make the gun more accurate..

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I'm responding to the bit I underlined, above. Your "But." comment above -- unless I've misunderstood your meaning -- disagrees with the bulk of what's been written or said.

I don't think anyone said a longer barrel makes a round shoot straighter. One responder said that with some barrels, longer means more potential for harmonic vibration, which can make accuracy worse. (Browning has a system to help with that in their rifles; I don't think it's a concern with handguns.)

Another responder noted that in Bullseye, a longer barrel coupled to slower/less hot loads, gives the shooter more time to move around, which increases the potential for human error. (I must admit, however, that THAT argument assumes a level of proficiency far beyond my scant talents... <sigh>)

A longer sight radius CAN help the shooter a bit, but in that situation it's the shooter who is doing better, not the gun. A telescopic sight might help the shooter, as well.

In both cases, If YOU aim better, it's not the gun that's more accurate, it's the shooter that's more accurate. The gun doesn't really care.

I think a 5" barrel is the best all around for open carry, but sometimes you just have to make do with smaller concealed carry sidearms.

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With my carry gun, a Kimber Custom Classic (MK I), a standard size M1911, I can ring a 12" gong all day long at 100 yards.

but if it makes a round shoot straighter and helps you aim better, i guess it does make the gun more accurate...or maybe makes the shooter more accurate might be the way to term it...?

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The last part is correct. It makes the shooter more accurate.

Sam Cade said:

For the most part, mechanical accuracy isn't a function of barrel length.

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THIS IS THE COMPLETE and final answer to the question asked.

I was assuming speed = straighter....maybe i meant "flatter"

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You're kind of mixing apples and oranges...

With a good gun, and uniform loads (consistency with round performance), the groups shouldn't be that different between a hotter or weaker load -- if you remove the "human" factor.

Hotter loads might mean the point of impact is different than with weaker loads, with the same weight bullet and design, but it doesn't necessarily mean that groups fired will be tighter/better just because the round is moving faster. Gravity affects each successive bullet in the same way -- so it's a constant in terms of accuracy.

I'm over-simplifying, but as long as the shooter can adjust the sights or change his/her point of aim, the likelihood of hitting the target shouldn't be that much different with hotter or weaker loads; if there is a difference (and you WERE talking about a longer barrel), it'll be more dependent on the sight radius than barrel length performance. (That said, I've seen target pistols with sights extended beyond the end of the barrel, to artificially increase sight radius. I guess that can work, too.)

Longer barrel means more velocity and higher spin rate. This can mean faster time-to-target and less drift, particularly at longer ranges. A longer barrel thus can mean greater accuracy.

A longer barrel can also mean reduced accuracy, however. In designs where the barrel bows or otherwise moves on firing, a longer barrel can mean greater deviation at the tip, which results in wider groups.