Barrel length and its effect on powder selection?

[MBTcustom]

I know a longer barrel is a whippier barrel.
And I assume that a shorter barrel needs faster powders.
In this same line of thought, do longer barrels prefer slower powders?
I am in the middle of a rifle build, and I am trying to decide on barrel length. I have the opportunity to build a custom rifle in 358winchester and I am going to be receiving a barrel that is 26" in length. Now most modern rifles have barrels that range in length from 20"-24".
What I am wondering is if the length of a barrel kind of pins you down to a certain speed of powder; like if you have a rifle with a 20" barrel you will most likely find the right powder on the faster side of the selection, while if you have a 26" barrel you will need to look at the slower powders.
I wonder if this is true simply because the last time I built a rifle with a 25" barrel, it definitely preferred the slower powders. Could have been a coincidence, but I would like the experts to weigh in and set me strait on this issue.
:drinks:
(by the way, I am building a .358winchester, and I am considering cutting the barrel to 20" to save weight, improve stiffness and keep the length of the rifle as short as possible, but I dont want to limit my powder selection)

[303Guy]

I was thinking pretty much the same as you with my 303 Brit Pig Gun with its 14.6" barrel (from breach face). I wanted the slowest powder that would work so as not to damage the boolit on launch. I ended up with a fairly slow powder - one that is too slow for the 308 Winchester let alone the 358 Winchester but is indicated for the 303 Brit. Well, that powder, H4350/AR2209 produces 2000 fps with a 194gr boolit from that short barrel with moderate pressure. So, it seems the answer is not that straight forward.

[stubshaft]

Longer barrels do not necessarily prefer slower powders, they can get much higher velocities by using them. Having a "whippier" barrel doesn't mean that it will be inaccurate either. The trick is to get the muzzle in EXACTLY the same spot on every shot. If you look at 22lr benchrest guns they all use tuners for just that purpose.

I have three barrels chambered for the 500 S&W, they measure 12", 15" and 25". Each one prefers a different powder charge but they all like the same powder. The 12" will not burn more than 26.5gr I have loaded it higher but the velocity increase is minimal which is a pretty goof indication that it is blowing the excess powder out of the barrel. The 15" uses the same powder but 32.0gr is about the most that it can use. Finally the 25" will take a slightly compressed charge of 36.5gr and get the most velocity. The powder I use is medium fast for this cartridge.

My answer to your initial question is YES, you would generally use a faster powder to get the best velocity out of a shorter barrel especially with an overbore cartridge.

[MBTcustom]

Having a "whippier" barrel doesn't mean that it will be inaccurate either.
I knew that, but I thought that the accuracy nodes where much more pronounced? I guess I dont know. Irregardless, this barrel is a pretty heavy contour so that's a moot point.
I do intend to use a scope on this rifle so sight radius is not an issue.
stubshaft's tests seem to indicate that extremely short barrels will strip velocity from the cartridge, given that a good powder has been found for that barrel, but that is not an issue for me because I will be using this rifle to ding steel, punch paper, and knock over whitetails and on my best day the range will be no further than 350yrds. This cartridge has enough punch to do all that even at a reduced velocity.

So I guess my real question is: Is there a disadvantage to using a shorter barrel? and how would I get a feel for how short is too short?
I wish I could experiment with this, but at $120 per test, a guy could go broke figuring out what somebody else already knew.
Thanks fellers!

[John Taylor]

On some cartridges every inch of barrel will equal about 50 feet per second in velocity, going from 24" to 20" could cost 200 feet per second. Also with a shorter barrel the muzzle blast will be more. If your a brush hunter the short barrel is a plus. If your shooting longer range the longer barrel is a plus. You can flute the barrel to take some weight off if that's a problem.

[oldgeezershooter]

There were tests done years ago by Homer Powley the foremost rifle ballistician of his day. He found that almost all smokeless powder is burned right in front of the cartridge.
In small-capacity cartridge using fast-burning powder, such as a shotgun shell the powder burns within an inch, while in a large magnum it might occur in three inches.
A small percentage of powder can be blown out of the muzzle but it's a tiny percentage. If a lot is blown out the muzzle, it's because the pressure is wrong for the powder in question.(Taken from "Handloader Magazine".)
There is a good article in this mag. about barrel length and the effect on velocity.
Oct.-Nov. 2006.

[oldgeezershooter]

These are the results from tests on barrel length.
1)Any load will perform differently in different barrels.
2)Any load will have its velocity gains plus losses.
3)No load sticks to the uniform "law" of 25 f.p.s. per inch.
4)The maximum loss in working lengths is about 12 1/2 f.p.s.
5)Velocity loss per barrel-inch is less with low velocity jacketed bullets than with the same bullets at high velocity.
6)Velocity loss is generally less with cast boolits than with jacketed type.
7)Velocity loss varies with the powder used.*

*Number 7 seemed to have no connection to burning rates of the powders.

[MBTcustom]

So It effects velocity, but not necessarily accuracy, or powder selection? I guess that Homer was stating that for a given powder, speed would be sacrificed?
I want to keep as much velocity as possible, but all I really care about is accuracy.

[felix]

Recoil control, barrel whip, and then, and only then, ES in that order. Time to target can be interchanged with ES in the ordered line-up, and would be based upon the realized accuracy obtained for the current conditions. Warehouse experiments have consistently shown that the non-compensated barrel length should be standardized at 21.75 inches for the component formulations used today. The undocumented assumption is that only condoms were used. ... felix

[MBTcustom]

"ES" ? Sorry felix you lost me. Are you saying that 21.75 is the ideal barrel length? Sorry, but this one went right over my head and I feel like its real important, can you explain?

[foxtrotter]

The Powley Computer gives almost a linear velocity increase with bbl length when using single base powders. I used his info when building my 25-06 and used a 30" straight taper bbl. The increase over published figures in a 26" bbl was about
50 fps/inch which agreed with the computer.

[Chicken Thief]

This will show how "much" the last 20" will rise max. speed (250fps with this powder and the charge is compressed!)
The difference between 20" and 26" is wisible but only past 350-400yds.

http://i295.photobucket.com/albums/mm153/Chickenthief/Skydning/Til%20andre/358Win.jpg

Chamber/barrel pressure on the left and by the red curve.
Boolit travel/barrel length at the bottom.
Boolit velosity at the right and by the black curve.

[oldgeezershooter]

I killed an Elk this year with my 45-70 #1 with 22" barrel and he was just as dead as with a 26" barrel!

[trench]

dead is dead, right? If you'd killed him with a 357, he'd somehow still be alive?

[Casting Timmy]

A longer barrel can be shortened if needed and rechambered if you want too. You don;t get to redo the short barrels as much as a longer barrel.

Personally I like short barrels, a guy I know likes longer barrels. He does have a good point that you can change calibers or recrown more with a longer barrel.

[jblee10]

I think the powders that are the best suited are determined by the cartridge, not the barrel length. I read somewhere that peak pressures are developed in about 4 inches of barrel. From there on, pressures are dropping. Longer barrels will have higher muzzle velocity, but sometimes not as much as you think. The 358 Win is a great round for a short barrel and still have a good expansion ratio. A 7mm STW would benefit from a longer barrel more than a 358 Win. Remember, the factory does not have load designated as long barrel or short barrel loads. The best load for a particular round is the best, regardless of barrel length. Just my thoughts.

[frnkeore]

Over the years, I've read article about shortening barrels and using faster powders to try to compensate for velocity lost. Each one that I read showed that if you got your top velocity with a slow powder in a long barrel, that same powder gave top velocity in the in the shorter barrel, just with more muzzle bast and flame.

Frank

[S.R.Custom]

Over the years, benchresters shooting the .308 Winchester have shown a preference for a 20" barrel for accuracy. My own personal experience in building .308s has confirmed this.

Now considering the .358, which is less overbore than the .308 --and of which I've likewise built a few-- a 20" barrel is more than enough barrel. And when you start to play the velocity vs. accuracy game with the .358, chances are you'll settle on IMR4320. Indeed, the most accurate combination I've observed in the .358 is the Sierra 225 gr SBT over IMR4320. One notable combination yielded just under 1 MOA at 200 yards... a Browning BLR we'd bobbed to 18".

[303Guy]

If I may make a suggestion, the muzzle blast factor is significant and the longer a barrel the lower the muzzle blast and the further away from your ears.In terms of hearing damage, unless you have a fitted suppressor the longer the barrel the better. While a short barrel is handy, a long barrel isn't that much less handy. A shrouded muzzle break might be legal as it's not a suppressor but the muzzle blast will still be significantly reduced along with the recoil. Then a shorter barrel would be less damaging then a longer barrel with such a device/

[MBTcustom]

So, is there a certain powder selection that always seems to give good results in a particular cartridge, regardless of barrel contour and length?

[S.R.Custom]

I wouldn't say "always." The preferred verbiage would be "more often than not." These are referred to as 'classic' loads.