barrel length for maximum velosity in 6.5x47L

[4Mesh]

On another thought, has anyone ever seen a person shooting and in the daylight, that rifle will have flames visible out the end of the barrel? Yep, most who've been to a 1K match have seen this. Not often from winning shooters anymore, but, it happens.

THAT rifle, will absolutely gain velocity with more barrel length. No question. When you see flames, there's unburnt powder. I have even seen people shoot, and in front of the bench when they were done, you could see complete unburnt extrusions of powder. Good chance that rifle will gain big too. Typically, that's accompanied by lots of flames. It's a spectacle at night.

Go to a PPC match and even with 21.5" barrels, you will be hard pressed to find unburnt powder laying on the ground, and believe me, some of these guys have the rifles stoked. Why is it so hard to understand that you can have both, more powder than the barrel can burn, and more barrel than the powder can push? Yea, the bullets come out either way...

@Todd, again, good chance that test was on something big, otherwise they'd have trouble with drilling. Yea, they probably had powder to spare. As to the other result, I'd need to know more what they were attempting to do for the velocities with various powders. Depending on what they did, it might seem crazy, or might make perfect sense.

 

[lefty o]

why not, because there is a pinch of dust inside a 22lr cartridge for powder, while there is a whole bunch of propellent inside a centerfire cartridge. like comparing a spitball to a wrist rocket. why is it so hard to understand your making claims as facts with no hard evidence to back up said claims.

 

[dk hunt 14]

First off; how many guys are winning long range matches and aggregates with long barrels? I see no aggs or records set with barrels over 30 inches. That ought to tell you something.

 

[4Mesh]

How much powder is inside a 22LR? I've seen them with 2.5gn. Why is 2.5gn not scaled down from 2?/3? grains that's going in a 47 case? Sounds scaled down to me? So what other differences are there that cause the bottleneck case to have infinite pressure, and no leakage?

Your examples have been shown not to apply (ship barrels and lengths). Where is your hard evidence that at 25000", a barrel continues to gain velocity? I'm going to say the trendline favors my theory, (especially since the hard 22data supports it already before 20"). What even empirical example do you have for these long barrels? Don't bother with the ship thing again cause their not even 1/2 as long per caliber as we're talking. Don't just say, "Well, it's true as long as we quit at 40" barrels with X powder, so it's true forever with everything".

Re-read my posts all you want. In fact, maybe you should just read what I actually said one time, instead of what you think I said, 20 times.

Very funny DKHunt. With you shooting a 48" Kreiger in 300WSM. How far down the aggs do you go till you find a shooter with a barrel under 30"?

 

[lefty o]

im going to only say this once, dont try and turn crap back around. you are the first individual to have brought up ship cannons, your the guy trying to compare 22lr's to centerfire cartridges. you are the guy that wants everyone to agree with his theories, but offer ZERO evidence to support his theories. thus far your evidence has been limited to "you have to accept this" .so far your part of this barrel length discussion is a joke, yet you seem to want everyone to accept that your an authority on it even though you have no proven science to back up any claim you have made. back up what YOU have stated, or accept it as theory only.

 

[dk hunt 14]

Lefty i went and reread 4Mesh's posts and i think you are taking what he said the wrong way. He is saying you don't gain enough per inch over 30 to justify the costs. I have never seen the long barrels help much except in big cases with slow powder shot on cold days in hunting season. I believe anything over 30 in 1000 yard match shooting hurts you more then it helps. Velocity is not where its at.

 

[mikecr]

It's always a balance..
The potential of shooting systems(w/resp to barrel length) is predictable.
If you take (10) 28cal blanks to their highest LR potential in 7WSM, you might end up with 3 or 4 that will consistently shoot 1/4moa at 100yds.
Take (10) 24cal blanks to their PB potential in 6PPC, and every one will consistently shoot 1/4moa at 100yds.
Regardless of weight:
The WSM will end up ~28-30"
The 6PPC, ~20-22"

The balance is in a 7WSM having far better odds of 1/2moa at 1Kyd, than any 6PPC.
And there is of coarse a lot more(tons more) to these applications than barrel length.
But in both cases, barrel length IS a big factor.
You won't consistently do much with a 7WSM in 22" barrel, or a 6PPC in 30".
No matter how much work you put into these, anyone who simply used better suited barrel lengths would hold a big edge on you. And that means they would outshoot you -in the long run.
So there is no reason to do this, or to deny that barrel length is a factor.

Why would a 22" 7WSM suck?
The cartridge provides capacity for slow burning powder, to push high twist heaviest per cal boattail bullets, to competitive performance levels -at long range.
But a short barrel does not allow enough powder to burn, or the pressure to drop enough, for clean muzzle release of a boattail.
This, at the very lowest point of stability, yet highest in trajectory influences, shot after shot.
Consider the high pressure fireball pushing on a releasing boattail at random angles, while robbing you of consistent velocities.
This is potential limiting, similar to a damaged crown, or flat out bad load.
You would also be giving up velocity to those competing against you, who's hats don't catch fire with shooting.

Why would a 30" 6PPC suck?
The cartridge provides capacity for fast burning powder, to push low twist mid-weight flatbase bullets, to competitive performance levels -at short range. It burns up it's fuel completely, and consistently, while releasing bullets clean, even in a short barrel.
Long barrels move more than short barrels in every respect, so there are prices to pay for longer than needed.
A 30" 6PPC would not be competitive at short range, because it wouldn't be accurate enough to beat 22" 6PPC shooters.
A 30" 6PPC would not be competitive at long range, because it hasn't the capacity to drive needed LR bullets.

I couldn't imagine anyone doing either..
Anyway, for a 6.5x47 to be competitive at 600yd, anyone could guess that a successful system would include a barrel between 25" to 28".
That is long enough given it's capacity, and LR bullets and powders available, to be accurate.
And it's not so long that accuracy potential is sacrificed for diminished velocity gains.
I think we all reach this barrel length balance -eventually.

 

[Tod Soeby]

First off; how many guys are winning long range matches and aggregates with long barrels? I see no aggs or records set with barrels over 30 inches. That ought to tell you something.

Simple...shorter tubes are easier to tune, stiffer, and are thus more accurate that long wippy tubes. Both short range and long range shooters have pretty much found the speed/accuracy happy place....short range guys are willing to give up a little speed for more accuracy, and LR guys are willing to give up a little accuracy for some extra speed. My thoughts are that if we could shoot indoor 1000 yard matches, our bbls would get shorter in a hell of a hurry.

Also...with length comes weight....most guys are on the very edge of making weight as it is. I would think the rifle ballance might come into play, also.