Accuracy differences in barrel lengths


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mfinley919
October 20, 2013, 06:20 PM
Are there any published findings on how accuracy changes based on barrel lengths of hand guns?

I'm kind of wondering how much a difference there would be in identical models, with just different barrels, such as a 1911 with a 5 inch barrel versus the same 1911 with a 3 1/2 inch barrel say at 25 and 50 yds?

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powder
October 20, 2013, 10:44 PM
It's the shooter. At those ranges, up to 100yds or so.

Sam Cade
October 20, 2013, 11:06 PM
Barrel length shouldn't have any effect on the mechanical accuracy of a service pistol, all else being equal.

9mmepiphany
October 21, 2013, 12:26 AM
If both guns are being shot out of a mechanical rest, the only difference will be the inherent accuracy of the barrel/gun.

If shot out of a rest with the same frame and different top ends, the difference will be how well the barrel is fitted to the slide.

If shot by hand, the difference will always be the shooter's ability to align the sights and press the trigger

RedAlert
October 21, 2013, 01:34 AM
I didn't see it mentioned so I would also mention that the longer barreled pistol will have a longer sight radius. This will aid the shooter to achieve greater accuracy.

Iggy
October 21, 2013, 01:52 PM
Mechanically speaking the accuracy should be the same. The longer sight radius will have the most effect.

rcmodel
October 21, 2013, 02:30 PM
From Sept, 2013 NRA American Rifleman magazine gun test.

Kimber Master Carry pistols.
Average group size of 5, 5-round groups from Ransom Rest.

Ultra Carry 3" barrel
2.80" average.
Best 5-shot group = 2.09"".

Carry Pro 4" barrel
2.02" average
Best 5-shot group = 1.18".

Carry Custom 5" barrel
1.65" average
Best 5-shot group = .57".

This is about typical in my experience over the years.

In actual stand on your hind legs and shoot them practice?
You have to be a mighty fine handgun shot to shoot a 3 1/2" gun nearly as well as a 5" gun.

rc

ArchAngelCD
October 21, 2013, 02:34 PM
Like said above, mechanically there will be little to no difference.

The longer barrel handguns are generally considered more accurate because the sight radius is longer making them easier to shoot well.

gym
October 21, 2013, 07:35 PM
If the barrel gets longer it becomes more like a rifle. Take the 357 carbine vs say a 6 inch model 19 or 686. It's going to be more accurate because of the length and stability and the length of the sight line, and the increased velocity of the longer barrel. You can get pretty accurate with an 8 I/2 inch barrel and a scope on a 357 or 44 magnum. It just depends on what distance they start to overlap for your particular use.
And of course you are limited to only a few cartridges made for both handgun and rifle, like the two I mentioned and 22, 38,44, 45, etc, it worked for the early days of carbines, not so much now. We all know how difficult it would be to have an AK or AR pistol, as your carry gun.

Deus Machina
October 21, 2013, 08:17 PM
From a purely technical aspect, certain designs could be affected by length--with a locked or braced portion at both muzzle and breech--but I can't think of any that follow that off hand.

The biggest difference would be that the sights are further apart, and there's no way to test the difference from sight radius and still remove the human component.

orionengnr
October 21, 2013, 08:55 PM
Barrel length shouldn't have any effect (sic) on the mechanical accuracy of a service pistol, all else being equal.

If both guns are being shot out of a mechanical rest, the only difference will be the inherent accuracy of the barrel/gun.
If shot out of a rest with the same frame and different top ends, the difference will be how well the barrel is fitted to the slide.
If shot by hand, the difference will always be the shooter's ability to align the sights and press the trigger

While each post is absolutely truthful, you may have to read between the lines a bit. "the shooter's ability to align the sights" is complicated by the short sight radius of the shorter pistol, whether it be a revolver, a 1911 or a G-whatever.

As far as the "press the trigger" part, that is a factor, but is utterly unrelated to frame size and sight radius.

Bottom line--when sight radii shrink below 5" or so, the shooter's ability is almost universally diminished compared with a longer barreled handgun.

There are people who can shoot a 1 7/8" j-frame snubby with astounding accuracy...but that is the result of many hours of practice.

For the rest of us "mortals", a 5-inch 1911 or M-27 is as good as it gets. As the barrel length shrinks, our ability to make five holes touch diminishes (at any given distance).

9mmepiphany
October 21, 2013, 09:16 PM
Just for clarity, be aware that a longer sight radius doesn't really make it easier to shoot more accurately. What it does is make it easier to to see alignment errors as all movement between the sights is exaggerated as the sight radius increases.

Some people find this movement distracting and will shoot a Glock G19 (4") better than they do a G34 (5"). Sight radius becomes less important as the difference in the gap on either side of the rear notch, around the front sight blade, increases.

In other words, the tighter the front sight appears in the rear notch, the more important the sight radius is to sight alignment for accurate shooting

BCRider
October 22, 2013, 01:37 AM
Kimber Master Carry pistols.
Average group size of 5, 5-round groups from Ransom Rest.

Ultra Carry 3" barrel
2.80" average.
Best 5-shot group = 2.09"".

Carry Pro 4" barrel
2.02" average
Best 5-shot group = 1.18".

Carry Custom 5" barrel
1.65" average
Best 5-shot group = .57".



That's fine for the Kimber line.

This same topic comes up reasonably regularly. In one of the previous threads mention was made of Ransom rest testing of some revolvers from 1.5 or 2 to 6 inch. The results in that test were far closer for spread in the groups from smallest to longest. It was almost insignificant as I recall.

All of which points that it's more about the longer sight baseline length. At least possibly on an individual basis up to a point as 9mm suggests above.

MachIVshooter
October 22, 2013, 01:59 AM
If the barrels are all of equal quality and rigidly mounted, the mechanical accuracy will be identical, regardless of barrel length*.

However........in a semi-automatic locked-breech handgun, the barrel may be able to wiggle slightly, even when the action is fully in battery. Well, a 5" barrel with 0.010" of wiggle at one end is going to have less angular variation than a 3" barrel with the same amount of wiggle.

That said, as mentioned, the biggest difference is in the shooter's ability to align sights. Once again, a .010" variation in sight alignment over a 7" sight radius has less angular variation than a .010" variation in alignment over a 5" sight radius.

*assuming a vacuum where TOF vs. environmental factors is a non-issue, and barrels rigid enough that the longer one has no more flex or whip than the shorter one

Sam Cade
October 22, 2013, 02:17 AM
http://www.thehighroad.org/attachment.php?attachmentid=190245&stc=1&d=1382422606

jmr40
October 22, 2013, 07:11 AM
While it is true that techically there would be no difference, in the real world there is. The simple fact is that it is easier to aim accurately if the front and rear sights are farther apart. Same reason rifles are always going to be shot more accurately than handguns when both are equipped with iron sights. With optics on either there isn't any difference when you compare barrel length and accuracy.

How much more accurate depends on a lot of factors. The quality of the sights, the individual guns, the shooters skills etc. One individual might not notice any difference between identical guns like 2 Glocks with barrels less than an inch different, but another might. There are darn few of us that can shoot a 2" snub as accurately as an 8" barreled revolver even though technically the 2 should be the same.

gym
October 22, 2013, 04:05 PM
For some reason I always shoot short barreled revolvers better than long barreled revolvers. But I found a 3-4 inch the most accurate for me in a combat course. Not true with Auto pistols though. I shoot a full sized 1911 better than a commander or smaller.
I lock the DS size gun like a vise, with very little movement. Even as a kid my uncles, "all experienced shooters" would be baffled how accurate I was with a 2 inch or under snubby.
I couldn't shoot my uncles matched pair of 38 target guns nearly as well, where he could get 1 ragged hole at 25 feet.

ratt_finkel
October 23, 2013, 04:09 PM
From Sept, 2013 NRA American Rifleman magazine gun test.

Kimber Master Carry pistols.
Average group size of 5, 5-round groups from Ransom Rest.

Ultra Carry 3" barrel
2.80" average.
Best 5-shot group = 2.09"".

Carry Pro 4" barrel
2.02" average
Best 5-shot group = 1.18".

Carry Custom 5" barrel
1.65" average
Best 5-shot group = .57".

This is about typical in my experience over the years.

In actual stand on your hind legs and shoot them practice?
You have to be a mighty fine handgun shot to shoot a 3 1/2" gun nearly as well as a 5" gun.
I think this bares repeating. Having seen my own ability go up and down over the years. Assuming the above were true for most reliable, modern handguns. Then you have a significant difference in accuracy. It's showing the mechanical accuracy of the longer barel to be 4 times better than the shorter barrel.

While this may not seem like much for a bench test. Most real world people would never be able to attain those results. Based on my experiences, the average shooter is lucky to do 3-5" groups at 15 yards. And I see plenty who cannot do that grouping at 3 yards. So let's say from the test above someone shooting at half the distance, so 12.5 yards. They are now shooing 3" groups with the 5" barrel. At 25 yards, that group has increased to 6" The 3" barrel is only capable of doing 12" groups at 12.5 yards. While the 25 yard results would be 24".

To me, that is a drastic difference in accuracy. But it also reflects as to how much the shooter has to do their own job.

Now in reality, those that can manage a 6" group with a 5" barrel 1911. I would guesstimate should easily be able to keep a 3" barrel 1911 within a 12=15" area at 25 yards. My 2 cents.

BCRider
October 27, 2013, 08:55 PM
Granted those Kimber values sure seem to suggest that. But I think you have to take this as more a factor of Kimber accuracy within their model lineup and at the level of precision they work at instead of making their results a blanket sort of comparison.

A few years back someone posted this same topic and someone replied with similar tests but using S&W revolvers. In that set of results the difference from short to long was more like 1.1:1 or 1.2:1 Basically a 10 to 20% difference from 1.5" to 8 3/8 inch in terms of accuracy.

So we should not be quick to jump to conclusions based on only one maker's products.

Archie
October 27, 2013, 09:40 PM
Barrel length does not substantially change the inherent accuracy of an arm.

Longer barrels usually make for longer sight radius, the longer sight radius gives a better view of sighting errors (as so rightfully stated by 9mmepiphany). Normally, this makes 'sighting' easier, which enhances accuracy.

There are many issues which affect accuracy. The sighting mechanism (iron sights or optical device) much maintain the same relationship to the barrel for every shot. The quality of the barrel.

A rifle typically has an accuracy edge over a handgun of typically three to one (i.e. a rifle will shoot a group at 100 yards the same size as a comparable handgun will shoot at 33 yards; OR, at the same range, the rifle will shoot a group one-third the size of the handgun.) However, the difference is not all in the length of the barrel. The rifle with buttstock can normally be held to a tighter sight picture than a hand only (even both hands) handgun.

I remember a bullseye pistol maker (I wish I could remember his name now) in the 1970s and '80s who built match grade .45 and .22 pistols with the barrel counterbored (muzzle recessed) to the point where the actual barrel with lands was only about three inches long. The last two inches of the barrel the bullet was actually not in contact with the barrel. Of course the slide was unchanged and so the sight radius was still the same as a 'normal' pistol. The theory was last second twitches of trigger break and so forth didn't disturb the sight picture until the bullet was 'free' of the movements of the pistol. That seemed to work. It didn't work enough to justify the added expense.

Back to rifles: A rifle normally shoots better than a handgun, but the accuracy difference between an 18" barrel rifle and a 26" barrel rifle is not so much - all other factors being equal.

Anyone remember the .38 Special wadcutter chambered pistols used in Bullseye competition (Colt Gold Cup and S&W M52)? Those pistols were designed for maximum accuracy in the 'centerfire' category and were not restricted to five inch barrels. (As I recall, at the time, they were restricted to a 10" sight radius.) Both guns were highly valued precision pistols, but they both were designed with 5" barrels. Since they were designed as target guns, they could have easily been made with six or seven inch barrels. But they weren't.

In some disciplines - international union rules, I believe - some pistols had barrels of 'normal' length, but had extended front sights that made a longer sight radius.

My point is this: If - with all other factors being equal - a longer barrel always gave higher accuracy, then all the bullseye guns would have barrels as long as the rules allowed. That does not show up in the world of competition.

98Redline
October 28, 2013, 12:51 PM
There is a difference between shootability and accuracy.

The bullseye guys are looking to bridge the gap between the weight of the gun and the longer sight radius. Take a look at some of the 5" 1911s with extended front sights. This allowed the same sight radius as a 6" gun with the lower weight of a 5" gun.

hentown
October 29, 2013, 08:35 AM
Longer barrels don't necessarily mean a longer sight radius, OF COURSE!!!!:evil:

mtrmn
October 29, 2013, 10:39 AM
Ammo and consistent grip makes all the accuracy difference in my handguns.

bullbarrel
October 29, 2013, 10:41 AM
Actually a longer barreled handgun is more accurate than a shorter one. I once tested a Smith Model 60 three-incher against a Taurus 608 four-incher which is ported. Penetration was greater for the Smith as its three-inch barrel was longer than the Taurus four-inch, since porting robbed the 608 of well more than an inch of its length. But take any barrel of longer length and you get more penetration. That equals faster, and because a bullet starts to drop the nanosecond it leaves the barrel a short barrel's bullet will get to the target a tad lower. Of course this is negligible but the case is made.

flatlander937
October 29, 2013, 12:59 PM
There was an article massad ayoob wrote... he found shorter barrels are more accurate in some cases in a copy of Combat Handguns.

Here is a thread with reference to it:
http://www.defensivecarry.com/forum/defensive-carry-guns/119451-uncanny-accuracy-g30-suggested-explanation-mas-ayoob.html

tuj
October 29, 2013, 07:39 PM
If we ignore sight radius (ie have a red dot or scope), I believe anything past 4 inches will shoot as well as anything out to 12". Velocity will be different of course, but I have a Pardini SP, Pardini GT and Les Baer PII that will all do 1.5" groups at 50 yards with proper ammo and none of those has a barrel longer than 5".

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