Barrel Lengths and Accuracy

We've all probably heard that, the longer the barrel, the greater the velocity! I've heard it referred to as approximately 50fps gained for every extra inch of barrel length, however, what about accuracy? Surprisingly, I've recently heard it said (without explanation) that, the longer the barrel, the 'less' accurate your rifle is! I always thought that, as long as you could practically 'tote' the thing, the longer the barrel the better off you are in both velocity 'and' accuracy!

What's your thoughts and comments on that?

I think that as long as the rifle is zeroed to then it doesn't matter.

If it's shorter it's more stout thus has less "whip" and should be more likely to be consistent, and barrel length can have an affect on speed to a certain degree but that's all dependant in your load also, a faster powder that burns completely in a shorter barrel is going to be more efficient than that same load in a long barrel where it burns out half way down and then pressure starts to drop

Shorter barrel = less dwell time in the barrel for the projectile = less time for rifle to move off intended target

All the theory is good, but when you look practically, benchrest shooters are getting excellent accuracy with their ppc's with barrel length of around 21", varmint for score shooters are using 24" barrels in their 30 br, medium and long range benchrest shooters are achieving excellent performances from 600 tp 1000 yrds using 28 to 32" barrels ( we are talking under 2" and 4" respectively for the best ones).

Jumping to the lighter rifles department, if you take a look at the regular posts from kiwi greg and what groups he can achieve with the light rifles he gets built ( including magnums with long skinny fluted barrels) and good reloading techniques, the "short barrel = more accurate" theory become a bit of a myth.

Apart from getting you closer to the target, I've read that longer barrels are considered more accurate as the nodes are further apart. Also gas turbulence at the crown is reduced as the bullet is no longer accelerating when it leaves the barrel and has entered its stable gyroscopic phase.

I had my 7mm-08 tikka cut down to 18 inches and suppressed and now I can consistently shoot half moa groups with it using factory ammo.
I used to average 1 moa groups and it was a bit fussy on ammo.

this question comes up from time to time . .. and the answer is . .. it doesn't matter.

you build or buy a rifle for its handling characteristics, its a total package, with compromises to do a job.

enough accuracy with enough velocity for the job

beware simple answers to all questions about anything, no exceptions !

As per previous runs of this thread, the long barrel equals accuracy is a hang over from iron sight days when the the longer sighting radius minimised sighting errors.
Short stiffer barrels are potentially more accurate than long wippy barrels. Having said that my 284 has a 33" barrel which allows me to use a full case (best load density) of the slowest burning powder possible to achieve my desired velocities without excess pressures. Also the Yanks for years have shot, very accurately, extreme long range events using specialised pistols. Loooong barrel 22s are also a thing of the past as it has been shown that the 22 bullet will actually start slowing down b4 exiting the barrel. Again, long barrels meant less iron sight sighting radius errors.

The answers are all anecdotal. the only way you'll ever know would be to do a proper experiment, and why would you when most rifles be it 16" or 32" will go sub MOA

Regarding 22lr, the most accurate bench rest rifles are built with about 24" long tube and they use muzzle tuners.
Yes the 22 bullet needs only 16 to 18" to burn all its powder, but the longer flexible barrel makes barrel tuning much easier.

By the way the reason tuners are used with 22 lr, is because the amo can not be tuned by hand loading, the variation of speed between each bullets is compensated by the different angles positions the muzzle takes when releasing said bullet, so that they all end up on the same area of the target.( hope that makes sense)

Not to me Friwi.

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Originally Posted by Rushy

Not to me Friwi.

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By moving the tuning device along the barrel you cam 'hange the resonating frequency and thus change the nodes in the wave of the barrel to time them for when the projectile is exiting the barrel

Here is a bit more information :
Smallbore accuracy

Using barrel vibrations to tune a barrel

Enjoy the reading

this one always puzzled me same with seating depth to some degree saw it explained differently the other day and it kind of made sense
barrel flexes a bit like a good fly rod if you shake the shit out of it,these nodes, that people talk about are the points along barrel length where barrel moves the least. if your get your muzzle at that point in theory the "whip" factor is minimalized eg the muzzle will be at same place each shot
you do it one of three ways
barrel length
seating depth
or tuning load with powder charge
or combination of last two eg tuning a load properly
back when just had factory a few different loads were tried till you found one that worked
benchrest shooters have used BIG THICK HEAVY barrels for years.some as fat as truck axles!!!! by making it heavy it CANT flex around bugger all as its too fat to flex and to heavy to jump (bit like this overweight truck driver really)
by shortening you sporter weight barrel it CAN POSSIBLY make it fatter and stiffer so like above target barrel more steady and less fly rod like.
hope my long winded ramble makes sense???

oh yeah...and long barrels are a right pain in the arse in the bush!!!!!!

From experience I have decided that longer thinner barrels are not necessarily less accurate but more difficult to tune. Also regardless of the dimensions nothing replaces quality/consistency of manufacture. I have had two Savage .308 target rifles with "Truck Axle" barrels, one shot fantastically and the other average. I also had a 300win mag savage hunting rifle with a long thin barrel that shot almost as good as the best of the two target rifles. That is until it had fired more than 5 rounds and groups started to open up.

Thicker barrels also tend to maintain performance after firing a few rounds, thinner barrels are more likely to distort and loose accuracy/change point of aim on heating. Once again it comes down to metallurgy and tuning of the barrel.

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Originally Posted by Micky Duck

oh yeah...and long barrels are a right pain in the arse in the bush!!!!!!

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Really...depends on how you hunting and what bush you in. I bushstalk all the time. Most of its in beech or native, some scrub but most places as soon s you get out of the car and hit the bush you might see sign so not travelling lighting fast. Because im always nearly holding my rifle, and not carried over the shoudler ive found the longer barrel no problem at all. My go to 243 is 22 inch and my 308 is 24 inch shooting 150sst at 2995fpss(chonry). Even the 24 inch 308 i never thought about cutting it down. If you stalking along, carrying your rifle it barely gets hung up, or will be a problem compared to a shorter model with say a thicker suppressor on the end .(yes, i have carried my mates short verison). Each to their own, but some of the bush is quite thick where i hunt and the longer barrel isnt a big issue for me.
Pig hunting is a different matter, as travelling faster a longer barrel is a pain in the arse, but if you stalking deer, you going slow, the slower the better so no problem really but thats just me

Barrel length itself makes no difference to accuracy, but long thin barrels shoot tighter groups when shortened, albeit at lower velocity. The quality of the barrel and the design of the profile are the critical factors. A good pistol barrel is potentially as accurate as a rifle (I have shot a 1.75 inch grpoup at 100 metres with an 8-3/8" S&W M29 .44 Magnum) subject to being of suitable quality. The old L1A1 SLR is usually good for about 3" groups with the standard skinny barrel, but shortened down to a couple of inches ahead of the gas block produces groups around 1" due to greater barrel stiffness. The ideal is to find a profile and length that gives an acceptable weight, reasonable barrel stiffness, and acceptable velocity for the ranges it is intended to be used at. From a hunting perspective MOA accuracy is not very important anyway. 2 -2.5 MOA is perfectly acceptable for bigger game at normal ranges (out to about 250 metres).

Thanks guys, never thought this topic would attract so much response! I feel it prudent for me to clarify something here, before well all get too carried away!

I'm talking a .300 RUM cartridge in a barrel length of 24 Vs 26"! A guy opened his yap and said that a 26" barrel would have more velocity for that particular cartridge (.300 RUM) than a 24, however, the 24" would have greater accuracy! (something that I'd never heard of before!)

I'm wanting to shoot 800 - 100 meters and was wanting to know if the shorter barrel would be more accurate (which given only 2" difference is probably completely undetectable!)

I tried to analyse it a little, in my head, by imagining a deer out at 900m and having a barrel with a length, of say 2" shy of that. You'd be able to point the muzzle anywhere you liked on it's body! I mean, you'd be able to shoot it behind the ear, like a 'BOSS'! Of course, some would argue that the gyroscopic whip, at that distance, would send the projectile off to Mars, but, then again, consistency is the key to accuracy, and if it's consistently sending the bullet off in 'exactly' the same direction, then all that would be required of thee is to simply alter your scope accordingly, no?

Bottom line is, we're only talking 2" difference, between 24 and 26", with a .300 RUM! IMHO 26" barrel is going to be better for powder burning for that particular cartridge, than a 24" would be, regardless of which type of powder you use, fast or slow!

The Truth About Barrel Length, Muzzle Velocity And Accuracy

I think the difference is ask yourself why a 300RUM v a 300 win mag. If you going to use a RUM which burns slower powders and more of it to get the full benifit of using heavier rounds compared to 300 win mag the extra barrel length gives you the full perforance for that CAL, burns the extra powder better and extra speed. 26-28 inch is what all the experts recommend otherwise you might as well just have a 300 win mag etc. At the same time as a hunting rifle its still going to work fine in 24 but isnt everything harder and more expenisve to get, ie brass, ammo etc and more recoil, noise so for the extra downfalls get the very best out of it....and that sounds like a min of 26 barrel. Some in the states use 30. Read a poll on the net on what barrel lenght for a 300 RUM out of 27-30 inch, 50 pcent picked 28, 33 pcent picked 30

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Originally Posted by deer243

I think the difference is ask yourself why a 300RUM v a 300 win mag. If you going to use a RUM which burns slower powders and more of it to get the full benifit of using heavier rounds compared to 300 win mag the extra barrel length gives you the full perforance for that CAL, burns the extra powder better and extra speed. 26-28 inch is what all the experts recommend otherwise you might as well just have a 300 win mag etc. At the same time as a hunting rifle its still going to work fine in 24 but isnt everything harder and more expenisve to get, ie brass, ammo etc and more recoil, noise so for the extra downfalls get the very best out of it....and that sounds like a min of 26 barrel. Some in the states use 30. Read a poll on the net on what barrel lenght for a 300 RUM out of 27-30 inch, 50 pcent picked 28, 33 pcent picked 30

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Hmm, yeah I'd certainly go a 26"!

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Originally Posted by chalkeye

The Truth About Barrel Length, Muzzle Velocity And Accuracy

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Very interesting article!
Interesting to note that, on the graphs shown, the 26" barrel, whilst not 'always' the most accurate, was, for the most part, right up there in accuracy, and velocity! I think, for a .300 RUM, a 26" would probably be a happy medium!

Only part of the story though - if you worked up a unique handload for each barrel length it might be a different story.

MOA angle precision is only part of the story.
A longer barrel will give higher velocity which primarily allows slightly reduced wind drift.
That's very useful at your ranges of 800m, where windage uncertainty is more important than gruop size or bullet stability and all the other sources of variation together.
I think you'll find that higher velocity also reduces small errors due to slope, air pressure/altitude and maybe other causes.
We assume you have the range to the nearest metre but errors can occur there too so if you range on a bush behind the deer you introduce a significant drop error at 800m.
I'm talking about stretching from 26" out to 30".
Small differences in magazine length and throating can allow greater velocities too and Brian Litz lists them as a significant "advancement in long range shooting".