User Panel
Posted: 7/21/2008 10:17:30 AM EDT
its a pretty commonly held idea that a longer barrel leads to more accuracy. but apprently most people on this site dont beleive that its true.
so can a 6" barrel really be as accurate at a 20" barrel. I find it hard to believe |
|
|
what kind of groups are you getting with a 4" barrel |
|
|
Maybe, but you get better range and velocity too out of a longer barrel.
|
|
Fixed. All other things being equal, a 6" bbl will be just as accurate as a 20" bbl.... |
|
|
yup |
||
|
Yes, but only from a standpoint that a shorter barrel has less muzzle velocity, so the bullet will drop more at a longer distance. |
|
|
+1 |
|
|
what about a 2" snub nosed 38 spcl. barrel. are you really saying that with propper rifling and loading, it could shoot sub moa?
|
|
I don't know. Center of mass mostly. I built it to go blam blam blam and be fun. I almost never sit there and see how accurate it is. But when I actually do carefully aim and try to hit a small point, it makes a ragged hole. Same as it did before the barrel was cut. |
||
|
Strange....
I thought that to a certain point, SHORTER bbls were more accurate... Less "whip" in the barrel as the projectile passes down it...take a 1' dowel and move it in your hand slightly, then a 4' dowel and do the same thing...the end moves a good bit more....however as pointed out above, a longer bbl does allow for longer sight radius with open sights... |
|
With everything else being equal, the short barrel is going to be stiffer, and have less movement than the longer barrel. From what I have seen a short barrel is as accurate as a longer one. It is not going to get the same velocity, and may have a shorter sight radius, but the accuracy should be as good.
I've got a group sitting on my desk here from a 11.5" AR w/ a red dot. It's between 1/2 & 3/4". That barrel (which I bought used) will shoot < 1" groups at 100 yards w/ decent ammo & optics. |
|
I can hit an iron maiden at 100 yards with one... the sights certainly don't help, though. |
|
|
Depends on a lot more than just the barrel like the type of powder, bullet weight, distance to target, type of rifling, etc, etc, etc...
|
|
Yes, it could, provided the action of the gun was capable (I don't know how the inherent accuracy of a revolver compares to that of, say, a bolt-action rifle. Probably not favorably). It would need optics, which would be a true pain to mount, or a machine rest. The bullets would also have a rainbow trajectory, but they'd hit in the same place. You could take an accurate .22LR bolt-action rifle, cut the barrel down to 2", and if you did a good job with the crowning and such it should remain just as accurate. |
|
|
Benchrest rifles are the most accurate rifles, they like 21.75" barrel length. These rifles are used for 100 and 200 yard shooting. For longer ranges it would be good to look at rifles built for long range shooting and emulate them.
Longer barrels are relatively less stiff for a given outer diameter which causes them to have more harmonic 'whipping' before the bullet leaves the barrel. And, since the bullet remains in the barrel longer, for say a 26" barrel, the whole rifle moves more in recoil before the bullet leaves the barrel. On the other hand, if the longer barrel gives the bullet a higher velocity it will travel through the turbulent air for less time and be more difficult for the wind to change it's flight path. Less time for the wind to act on it and more difficult to force a deviation from it's path. 20 to 22" for the win at least for shorter ranges like out to 300 yards. My benchrest rifle and benchrest style varmint rifle do great at 500 yards too. |
|
But with the difference in lengths...........how can all else be equal?? While benchresters (Who have weight limits)have reletively short barrels compared to F-Class , I believe that if they could get the same accuracy with a 10" barrel....by God they would use that weight they save elsewhere . I think folks mistake decent accuracy of modern barrel makers .....that get away with 16 and 20 inchers......to that of old styles that used to be acceptable at 24 inches. And none of what Ive stated has even begun to take into considerations of waisted gasses being expelled from a short barrel....before they are thru pushing the bullet. Pistol caliber bullets , for the most part , are done being pushed much sooner....so the remaining length of barrel is just friction. Show me serious varminters, benchresters ,F-Classers, etc.....that are competing with a stubby barrel |
||
|
Consistency = Accuracy
Shorter barrels means lower velocity, more bullet drop, but can be just as consistent as a long barrel. Shorter barrels usually means shorter site radius, which makes it harder to aim consistently. Shorter barrel means the front sight is much closer to your eye, which makes it much bigger compared to the target. |
|
Mechanical accuracy is not linked to barrel length. Practical accuracy is. (More velocity = flatter trajectory and less time to bullet impact, longer sight radius, etc...)
|
|
At 300 yards with an EOTech I hit 24/30 rounds on a human silouette target with a 10.5" barrel.
YMMV |
|
Does a 6" 38 Special shoot sub-moa ? I think alot of the misconception is what definition of "accuracy" are we talking about. A longer barrel (to a point) will give more velocity then a shorter one. The higher velocity means that outside forces have less time to act upon the projectile in flight. So you may be more accurate with a longer barrel at very long range. However given the absence of outside forces the gun is not more accurate then one with a shorter barrel. Within most normal ranges for a particular firearm the barrel length has no affect in accuracy. I have seen test done with a 44 magnum revolver that went from 12" barrel down to 2 or 4" with no effect at 50 yards. And have seen 308 rifles go from 24" to 16" with no effect at 300 yards. (the zero may change but not the MOA) . Why do you assume a longer barrel will mean more accuracy ? |
|
|
It helps on the mini-14 rifle.
It help ever more to attach another rifle too it. |
|
You just stated it in your post ( until we are competing,waging war,or defending ourselves in a vaccum) Now if a weapon will perform its intended task with a shorter, and thus,lighter/more manuverable barrel..............by all means ...use it. And really.....what's the realistic difference between a .300 inch group compared to a .400 group in an urban enviroment anyways? But all the arguments are moot (to me) until the benchresters and long range classes (that have weight restrictions)move to a much shorter barrel. They are ,for the most part , our ultimate source of accuracy info and technology AFAIC. |
||
|
When the bullet starts to move, the firearm reacts. With shorter barrels, there is less mass to resist movement and the reaction is greater.
Sure, the longer barrel has longer reaction time. But this is why a 2" snub nose .38 won't be as accurate as a 6" |
|
This. |
|
|
Run optics & the sight radius problem is a non issue. You're then trading a lower velocity for a stiffer bbl & less dwell time in the bbl. |
||
|
Assuming you put a scope on a 10" and a 20" AR,
assuming you know the bullet weight, BC and muzzle velocity, would both be able shoot the same group at 100, 200 or 300 yds? |
|
Barrel "whip" (resonance of the barrel during firing) will least affect the bullet as it leaves the barrel at a specific barrel lengh. So depending on the particular gun and load, accuracy would decrease with an increase or decrease in barrel length from optimal... right?
|
|
You haven't seen the new BMG's they are 10in barrels now.............. |
|
|
My money is on the 20" . .223 , 6.8 , .308...............heavy barrel in both lengths , both made by the same quality maker (Lilja, Krieger, Hart, etc)to optimize the given length.....the 20" will prevail over a 10" every time under identical conditions. Ill put up a years ARF membership too Any takers??? |
|
|
And adding muzzle blast, and therefore flinching. |
|||
|
this |
||
|
The short barrel's advantage is reduced barrel time; the bullet is in the barrel for less time while the shooter is wobbling around.
A long barrel has some aiming advantage by separating the sights. Combine the two by using a barrel extension. A scope sighted rifle doesn't care, to a point. I've shot 11 inch barrel AR's with a medium contour barrel that will knock the hair off a gnat farther than you can see; they shot just as well as 20 inch barrels. The trick was the custom blanks and precision work. A heavy barrel will be more accurate when many shots are repeated as it can soak up the heat. A light barrel can put shots into one hole, too, but you'll need to wait for the barrel to cool after the second or third shot. There are more factors than just long or short and no one can make that claim without a pile of information explaining the specifics. |
|
Agreed. ...But since even this thread is full of hard-heads I guess I'll step up. I have a 16" M4-gery that I plan on cutting to 10.3 in then next few weeks. I'll try to do a before and after. Judging by the way my 5" AR shoots, I'd have to say it won't matter one bit. |
||
|
This hard head would love a before and after report. |
|||
|
That's Sometimes true.
A couple of years ago I wrote of a time when I took my 11½ Upper shooting at targets 200 yards away. The accuracy was almost as good as my Standard 20 inch barrel was. On the other hand I would never shoot the 11½ at a target 400 or more yards away. |
|
Thus causing some short barreled (sub 9") AR's in 5.56mm causing bullets to start 'Arc-ing' or spinning off in random directions like a paintball with backspin. Often leading to 'Keyholed' targets and significantly decreased accuracy out past ~150 yards. (One ~7" AR I've seen show keyholing start even within 95 yards) I think this is a liability for a defensive weapon in a public setting. The .45 ACP 4" barrel will (with reduced velocity) still sufficiently stabilize its heavier bullet out to 200 yards with decent accuracy. |
||
|
Technically, a shorter barrel leads to GREATER accuracy, all other things being equal.
Why? The biggest key to tight groups is barrel harmonics. When you shoot, the barrel vibrates, just like a tuning key. Hand loaders "tune" their loads by using different powder and bullet combinations to where the bullet leaves the barrel on a node rather than a swing. A shorter barrel leads to less "whip" or vibration of the barrel, and thus usually results in greater accuracy. |
|
Seriously, I will take the gun out this weekend and shoot some groups. I'll send it to ADCO sometime in the next ~2-3 weeks. Just give me some time. I don't have any handloaded ammo, so the green-tipped stuff is going to have to do. |
|
|
I bet if I had a long barrel I could get groups to touch no problem. If your request is 100 yards, I'd just use a 100 yard barrel
|
|
So again........why are the benchresters shooting a 20 inch or so barrel? They would love to move that weight down and back into the stock......if they could they would. |
|
|
The ammo is too inconsistent.......try some Hornady TAP or some Black Hills if you want decent results. Regardless............Id be interested in the results. Thanks. |
||
|
Oh and folks...........dont take me wrong. Id love someone to de-bunk my beliefs.
Id much rather run a shorter barrel on my weapons!!! |
|
You can somewhat compensate for that by using a small width (like .052) national match front sight post. |
|
|
Aren't 16" barrels quite common with benchresters? The folks shooting 6mm PPC at 100 yards that is.
As far as F Class, isn't that a much greater range? And from unsupported positions? A barrel too short would lead to balance issues, and the lower velocities would make for more air time on the bullet as well as greater compensation for hold over. If I had a Ruger Charger, I would take a stock 10/22 barrel on it, mount it in a vise, and progressively cut the barrel down in 2" increments. Recrown and shoot 10 shot groups at 50 yards all the way down to 4" or so. I only have 10/22 rifles however and I'm not paying a $200 tax to sort this mess out. |
|
There's way more to a barrel than what you see on the outside.
If you start hacking a barrel that does not have a uniform bore, or choke at the right location, you'll find the shortening makes the gun shoot worse. Let's say you cut the barrel off at a location where the bore is larger than in front of the chamber; now you've created a barrel with a flared bore at the crown, the worst possible condition as the bullet was squeezed smaller as it entered the barrel, and now it's rattling at the exit. The ideal barrel has a perfectly straight circular bore with constant diameter and perfectly concentric in the center of the outer diamter. The best we can do is get the bore as near concentric as possible at the chamber and muzzle and lap some choke in so the bore diameter is always decreasing from the chamber to the muzzle, with the crown as near normal to the bore centerline at the muzzle as possible. Some of you need to seek out the precision shooting games nearby to learn about the state of the art and the why's first hand. The trend in rimfire benchrest is toward long skinny barrels with tuners. The main proponent of this doesn't understand the physics, but he knows it works and his rifles are very hard to beat with the right shooter operating them. The reason it works is because the less stiff barrel is easier to control with the tuner. Centerfire benchrest guns for 100 to 200 yard matches have barrels in the 20 to 22 inch range. That's partly determined by the weight rules, and partly by the bore geometry. Long range benchrest shooters want a longer barrel to build speed; you control what you can and minimize the wind's effect as much as possible. As far as irons on AR's, even the longest stock configuration guns have abysmally short sight radiuses. The hot shots in the highpower game don't appear to be too handicapped, but those guys and gals have skills independent of the sight radius "handicap" that cross over to other shooting sports and they'll be hard to be in any game they enter. If you're shooting shitty off the rack barrels, particularly at the ever popular dirt clod target, there's no point arguing this. You'll be able to find all sorts of examples that all provide contradicting evidence to support whichever side you want. |
|
Within a certain range, shorter barrels CAN be more accurate than longer barrels. But let us be sure, here, we are not talking about comparing the accuracy of a 20" barel to the accuracy of a 3" barrel. 20"-16" and maybe a little shorter.
A) as the length of a barrel gets shorter the barrel gets stiffer (to the 4th power if anyonoe is interested: x**4) But this is counteracted by B) as the barrel gets shorter the barrel vibrations run up and down the barrel more times by the time the bullet leaves, thus making it harder for the bullet to leave when the vibrations are "away from" the muzzle. See Optimal Barrel Time and Optimal Charge Weight, ANd Audette Ladder while you are at it. Thus C) as a barrel gets shorter it may be more accurate, but it may ALSO be harder to find that one load that shoots to the barrels potential. In addition: D) as the barrel gets shorter the muzzle report get louder, doubling in sound pressure for each 3"-ish of barrel shortening. At least in 223/5.56 much of the terminal damage potential resides in the velocity of the bullet at impact. Short barrels don't emit the bullets as fast and thus there comes a barrel length that is so short the ammo does not perform "in target" as it was intended. So, if one is comparing a 24" bolt rifle to a 20" bolt rifle, it is very conceivable that the 20"-er would shoot better on average. And Google up "Houston Warehouse" for the complete story on how accurate can guns be made, tested, an tuned. In rubuttal to the short barrel theories: notice that the PALMA guns are very long barreled, and shoot pretty darned accurately by anyones measure. Thye need the 28"-32" lengths for sight radius amd muzzle velocity to ensure the 155 gr SMK projectile stays solidly supersonic at 1000 yards; often getting well over 3000 fps at the muzzle. Also note that magnum calibers generally need a longer barrel so that the MV potential of the weapon can be delivered in practice. |
|
my guess is this: if they ran short barrels they would have to SBR, which could cause issues/pain in the ass if they wanted to travel to shoots. this does not address why they just don't run 16 inchers. |
||
|
YES! On paper. But killing range is lessened greatly(I know off topic).
|
|
Yeah I won't be throwing a 10 inch barrel on my precision 300wm anytime soon. Distance to whatever meters might be the same but you throw a little wind into the mix especially with an inefficient round like a 9mm or a 38 special that thing will be blown all over place like a Marine on Liberty call in thailand. Like it was said what do you mean by accurate? What distance? Precision rifle accurate or hitting a man sized target on opposites sides with 2 shots accurate. A short barreled rifle is not going to be as accurate as a long barreled rifle past say 100 meters maybe 200 depending. Can the SBR hit the target maybe? Can it hit it as accurately as a Lilja or Hart? nahhh but they are also precision barrels for various reasons like quality control, design, thickness which makes it heat up slower and more uniformly. |
||
|
Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!
You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.
AR15.COM is the world's largest firearm community and is a gathering place for firearm enthusiasts of all types.
From hunters and military members, to competition shooters and general firearm enthusiasts, we welcome anyone who values and respects the way of the firearm.
Subscribe to our monthly Newsletter to receive firearm news, product discounts from your favorite Industry Partners, and more.
Copyright © 1996-2024 AR15.COM LLC. All Rights Reserved.
Any use of this content without express written consent is prohibited.
AR15.Com reserves the right to overwrite or replace any affiliate, commercial, or monetizable links, posted by users, with our own.