Which barrel profile would act stiffer?

[darkangel_r2]

Not true necessarily. A .338 bore barrel of identical external dimensions is both stiffer and lighter than a .224 bore barrel.

Interesting, mine and liljas comparison has it being VERY slightly less stiff when increasing bore diameter.

But that being said pressure dynamics and force on the barrel drastically increase with bore diameter. 60k psi in a .224 bore is way less actual force on the barrel than 60k psi in .338.

This is the same reason a larger bore diameter can drive a bullet of the same weight much faster than a smaller bore. Think of 308 pushing a 200. You would be hard pressed to get 2600 fps out of a 24" but 338 federal can do it easily.

The higher the force on the barrel the more the barrel will move.

 

[darkangel_r2]

Does a rifle barrel need to taper for any reason towards the muzzle?

 

[INTJ]

Not true necessarily. A .338 bore barrel of identical external dimensions is both stiffer and lighter than a .224 bore barrel.

Stiffness does not equal accuracy. The more steel the better the barrel dampens harmonics. Comparisons obviously need to be made of barrels with the same bore size and length. This isn't theory, it is observed experience...........

 

[mauser284]

Anyone dumb enough or young enough to carry a F-Open rifle into the hunting field deserves what he get's! LOL

In hunting outside of varmint hunting from a rest and lots of targets in rapid fire like P-Dog Hunt does not need a heavy rifle designed to shoot long strings.

In true hunting the first cold bore shot is the most important and most accurate and you need a decent follow up shot. Your third, forth or fifth shot will be garbage compared to your first 2. The lightest pencil barrel will do that just fine with out slowing you down or forcing you to take up weight lifting just to carry and shoulder your hunting rifle!

Real hunting rifles not designed for mall ninja's or tactically live action role players do not have varmint barrels, huge heavy nightforce scopes or tripods. The best hunters in the history of the Earth using smokeless powder did it with fairly light weight rifles in mostly non-magnum chambering and often with out exotic rifles owned by the wealthy. Often the wood stock weighted more than the barrel.

Do your home work on the animal you intend to hunt, learning how to range and read the wind, stalk, and bait an area is far more important than a heavy barrel. In fact I am taking off a heavier 5R threaded factory barrel to put a longer, lighter, non-threaded non-5R barrel on a 30-06. Why? The barrel is 3 inches longer, weights less, faster twist, custom chamber for long heavy ELD bullets, is higher quality custom barrel and it is SS and looks cool.

When I see a guy with a heavy barrel, huge heavy tactical optic, heavy tactical scope rings or a bipod on a hunting rifle the first thing I do is laugh. The second things I normal do is think about Sylvester Stallone in a Rhine Stone Cowboy in a Rhinestone Cowboy getup on a white horse! LOL

So what do you intend to do with it? What are you going to shoot? How many shoots in row with out letting the barrel cool. You must not get out to the reloading bench much because a heavy stiff barrel does not at all mean you will get more loads with less POI shift at all! LOL You are attributing characteristic to the barrel based on perceived stiffness or mass or the like that does not exist!

If what you believe to be true was true BR and F-Open would be idiot proof and easy! LOL

Lots of mass for any given length of barrel only lets you fire more round before heat causes the barrel to drift nothing else. Mass does next to nothing on normal cartridges for the first 3 shots outside of mitigating recoil some. From shot 3 to 20 in rapid fire it makes a huge difference as the barrel heats up.

It's ok to hate me I burst a lot of bubbles because I am actual into science and engineering when it comes to machinery not feel good feeling or popular marketing nonsense!

Other than initial zero and load development bench shooting a hunting rifle is like dyno tuning a race car instead of tuning it on the track. A lot more to winning races than just the engine likewise a lot more to hunting than punching tight groups in paper from a bench unless you hunt from a bench some people do!

 

[darkangel_r2]

Anyone dumb enough or young enough to carry a F-Open rifle into the hunting field deserves what he get's! LOL

In hunting outside of varmint hunting from a rest and lots of targets in rapid fire like P-Dog Hunt does not need a heavy rifle designed to shoot long strings.

In true hunting the first cold bore shot is the most important and most accurate and you need a decent follow up shot. Your third, forth or fifth shot will be garbage compared to your first 2. The lightest pencil barrel will do that just fine with out slowing you down or forcing you to take up weight lifting just to carry and shoulder your hunting rifle!

Real hunting rifles not designed for mall ninja's or tactically live action role players do not have varmint barrels, huge heavy nightforce scopes or tripods. The best hunters in the history of the Earth using smokeless powder did it with fairly light weight rifles in mostly non-magnum chambering and often with out exotic rifles owned by the wealthy. Often the wood stock weighted more than the barrel.

Do your home work on the animal you intend to hunt, learning how to range and read the wind, stalk, and bait an area is far more important than a heavy barrel. In fact I am taking off a heavier 5R threaded factory barrel to put a longer, lighter, non-threaded non-5R barrel on a 30-06. Why? The barrel is 3 inches longer, weights less, faster twist, custom chamber for long heavy ELD bullets, is higher quality custom barrel and it is SS and looks cool.

When I see a guy with a heavy barrel, huge heavy tactical optic, heavy tactical scope rings or a bipod on a hunting rifle the first thing I do is laugh. The second things I normal do is think about Sylvester Stallone in a Rhine Stone Cowboy in a Rhinestone Cowboy getup on a white horse! LOL

So what do you intend to do with it? What are you going to shoot? How many shoots in row with out letting the barrel cool. You must not get out to the reloading bench much because a heavy stiff barrel does not at all mean you will get more loads with less POI shift at all! LOL You are attributing characteristic to the barrel based on perceived stiffness or mass or the like that does not exist!

If what you believe to be true was true BR and F-Open would be idiot proof and easy! LOL

Lots of mass for any given length of barrel only lets you fire more round before heat causes the barrel to drift nothing else. Mass does next to nothing on normal cartridges for the first 3 shots outside of mitigating recoil some. From shot 3 to 20 in rapid fire it makes a huge difference as the barrel heats up.

It's ok to hate me I burst a lot of bubbles because I am actual into science and engineering when it comes to machinery not feel good feeling or popular marketing nonsense!

Other than initial zero and load development bench shooting a hunting rifle is like dyno tuning a race car instead of tuning it on the track. A lot more to winning races than just the engine likewise a lot more to hunting than punching tight groups in paper from a bench unless you hunt from a bench some people do!

I would suggest you read the OP more carefully. The final rifle will weigh less than 11 lbs with ammo and pod. And the question is which profile will minimize poi shift between different loads. Not which would allow the most consecutive accurate shots from the same load.

 

[Hohn]

Stiffness does not equal accuracy. The more steel the better the barrel dampens harmonics. Comparisons obviously need to be made of barrels with the same bore size and length. This isn't theory, it is observed experience...........

I didn’t say it had anything to do with accuracy. I was just pointing out an error of factual assertion about basic beam stiffness.

Damping is an intrinsic property and also has nothing to do with mass. A heavy bell can ring a long time. Rather, stiffness and mass combine to determine the frequency response and the frequency determines the amplitude of a displacement for a given acceleration.

The goal of a stiffer heavier barrel is to minimize the displacement due to vibration.

 

[Hohn]

Harold Vaughn found in his research for “rifle accuracy facts” that barrel weight, not stiffness per se, was the more important factor for overall accuracy. This is because the barrel tends to receive more vibration than it creates, so weaker coupling to the action (primary source of distortion) reduced barrel vibration.

I’d caution about extrapolation from his Winchester 70 action to modern custom that’s much stiffer.

Fundamentally, any action which uses a traditional recoil lug is inviting significant action distortion (and thus barrel vibration) under recoil. This is why I believe flat bottom actions that distribute recoil forces are preferable. Ideally, you’d use a “collar” that is axially symmetrical to the barrel.

 

[Rob01]

I’d put a funny meme here about heading down the rabbit hole but the OP was not happy with my last attempts at levity so just know the thought is there. lol

 

[JFrank]

I would suggest you read the OP more carefully. The final rifle will weigh less than 11 lbs with ammo and pod. And the question is which profile will minimize poi shift between different loads. Not which would allow the most consecutive accurate shots from the same load.

Sir'
Why haven't you asked the guy at Northland shooters supply these questions ?
Those barrels are relatively inexpensive enough to buy one of each profile , test your theory and decide for yourself which has the most inherit accuracy and report back with your findings in great detail as it seems not one person has satisfied your original question over nine pages it has to be time to move on .
A short while back a question was asked and rebuttled to the point of stirring the pot so much the boss got pissed and not only banned the member deleted the entire thread.

 

[darkangel_r2]

Sir'
Why haven't you asked the guy at Northland shooters supply these questions ?
Those barrels are relatively inexpensive enough to buy one of each profile , test your theory and decide for yourself which has the most inherit accuracy and report back with your findings in great detail as it seems not one person has satisfied your original question over nine pages it has to be time to move on .
A short while back a question was asked and rebuttled to the point of stirring the pot so much the boss got pissed and not only banned the member deleted the entire thread.

When everyone told me they were so close that I would not notice a difference on target I knew I couldn't go wrong with any choice so I wanted to see if experimentally tested theory could winnow it further. It did. Out of the original 3 I would go with light palma. This barrel is not going on this years hunting rifle so I have time.

But now I am interested in barrel design as I now have some tools and knowledge that can help. And I may do a custom contour from a cut rifle manufacturer if I can get some more information here.

I need to know if a rifle barrel has to taper toward the muzzle. Is there any reason this needs to happen mechanically?

 

[JFrank]

When everyone told me they were so close that I would not notice a difference on target I knew I couldn't go wrong with any choice so I wanted to see if experimentally tested theory could winnow it further. It did. Out of the original 3 I would go with light palma. This barrel is not going on this years hunting rifle so I have time.

But now I am interested in barrel design as I now have some tools and knowledge that can help. And I may do a custom contour from a cut rifle manufacturer if I can get some more information here.

I need to know if a rifle barrel has to taper toward the muzzle. Is there any reason this needs to happen mechanically?

Call Kreiger barrels. They might know.

 

[INTJ]

I didn’t say it had anything to do with accuracy. I was just pointing out an error of factual assertion about basic beam stiffness.

Damping is an intrinsic property and also has nothing to do with mass. A heavy bell can ring a long time. Rather, stiffness and mass combine to determine the frequency response and the frequency determines the amplitude of a displacement for a given acceleration.

The goal of a stiffer heavier barrel is to minimize the displacement due to vibration.

I was not addressing stiffness at all. The fact is a heavy steel barrel will nearly always shoot more accurately than a lighter contour barrel. That is not even debatable.

It's not the length of time the barrels "rings" it's the amplitude of the vibrations, and heavy steel barrels dampen vibrations better than light barrels.

Speaking off stiffness, carbon fiber is supposed to be very stiff, yet carbon wrapped barrels almost always shoot worse than steel barrels of similar or lesser contour. There is probably more going on that just the stiffness of the carbon, as there is also resin in the carbon wrap. However, the steel barrel liner is very thin, and many of these carbon wrapped barrels act like a skinny steel barrel.

 

[darkangel_r2]

I was not addressing stiffness at all. The fact is a heavy steel barrel will nearly always shoot more accurately than a lighter contour barrel. That is not even debatable.

That has been my experience as well.

It's not the length of time the barrels "rings" it's the amplitude of the vibrations, and heavy steel barrels dampen vibrations better than light barrels.

Correct Its energy in vs response. Fire cracker in a glass of water creates a huge response. Same fire cracker in a pool does very little. Same energy into different amounts of mass gets two very different responses.

Speaking off stiffness, carbon fiber is supposed to be very stiff, yet carbon wrapped barrels almost always shoot worse than steel barrels of similar or lesser contour. There is probably more going on that just the stiffness of the carbon, as there is also resin in the carbon wrap. However, the steel barrel liner is very thin, and many of these carbon wrapped barrels act like a skinny steel barrel.

What I have seen that they do is they line up their cold shots and reduce dispersion between loads better than traditional barrels of the same weight. But since the two materials have different heat transfer and thermal expansion rates it screws up strings of fire worse than a traditional barrel of similar weight.

So it will put different loads closer together for their cold bore shots, but will have worse performance for groups over just a few shots in length. Good for hunting as just a few shots is what you need. Expensive though. Probably annoying to do load dev on too.

 

[garandman]

Fascinating.

 

[INTJ]

What I have seen that they do is they line up their cold shots and reduce dispersion between loads better than traditional barrels of the same weight. But since the two materials have different heat transfer and thermal expansion rates it screws up strings of fire worse than a traditional barrel of similar weight.

So it will put different loads closer together for their cold bore shots, but will have worse performance for groups over just a few shots in length. Good for hunting as just a few shots is what you need. Expensive though. Probably annoying to do load dev on too.

I have shot a bunch of carbon wrapped barrels this year, and yes, they can be a pain in load development.

I haven't really seen them put the first two shots closer together than a steel barrel, but similar to what you described, I routinely see carbon wrapped barrels shoot well for two shots then open up. Like you said, fine for a hunting rifle and similar to a very light contour steel barrel.

Benchmark told me they worked hard on their carbon barrels and got as much resin out of them as they could. They do seem to shoot much more like a regular barrel.

 

[darkangel_r2]

I haven't really seen them put the first two shots closer together than a steel barrel,

What I meant is the poi would probably move less between different loads, as it is mechanically stiffer than the same weight steel barrel. But the heating properties screw its performance after just a few shots.

Have you ever put a strait jacket on a barrel?

 

[jimmymac]

Have you ever put a strait jacket on a barrel?

I may need one after reading this thread.

 

[INTJ]

What I meant is the poi would probably move less between different loads, as it is mechanically stiffer than the same weight steel barrel. But the heating properties screw its performance after just a few shots.

Have you ever put a strait jacket on a barrel?

I have had straight contour barrels, and then shoot VERY well.

I don't think stiffness by itself has much to do with POI. I think it's mass in the barrel that dampens oscillations, and that is what minimizes POI shift and dispersion. Of course it isn't only mass, like @Hohn pointed out, as the shape of the barrel has an
impact as well.

A resin impregnated carbon wrap complicates things, and I don't think a carbon wrapped barrel dampens harmonics remotely as well as a steel barrel.

Again, I know a lot more about WHAT works than why........

 

[garandman]

Again, I know a lot more about WHAT works than why........

I have no dog in this kennel, but this ^^^ speaks to a significant point, in my mind...

When we don't know the "why" we really don't know the "what" ... at least not in a way that'll help others.

The "what" is anecdotal.... what worked in a (my / your) narrow, specific, personalized, limited instance(s) Our "what" may well not work for their "what." The "why" helps others know if our "what" will work in their specific, personalized, narrow situation.

As such, the "why" really matters quite a bit.

I can't fault anyone for not knowing every "why." But I can see why others want to know the "why." We don't all have unlimited time / money / desire to try the 3 different "what" answers most gun questions generate.

I've learned gun tech has truly few universal absolutes.

Exception to my general rule: those who have several dozen / hundred or more guns or builds to draw on that experience. Some here do actually carry those credentials.

 

[darkangel_r2]

I have had straight contour barrels, and then shoot VERY well.

Good. I was just wondering if there was any reason they needed to taper any toward the muzzle.

I don't think stiffness by itself has much to do with POI. I think it's mass in the barrel that dampens oscillations, and that is what minimizes POI shift and dispersion. Of course it isn't only mass, like @Hohn pointed out, as the shape of the barrel has an
impact as well.

A resin impregnated carbon wrap complicates things, and I don't think a carbon wrapped barrel dampens harmonics remotely as well as a steel barrel.

I'm fairly sure they both weight and stiffness contribute to dampening vibration amplitude. The cantilever beam bending equation that lilja uses has modulus of elasticity in the denominator meaning the stiffer material the barrel is made from the less deflection when the same force is applied. I think the problem with using stiffness as a primary dampening mechanism is that it also has the negative effect of increasing the frequency of vibrations possibly making the node windows smaller. But simultaneously a stiffer barrel can dampen amplitudes of higher order vibration modes into irrelevancy. So it is a very dynamic question.

But just adding mass at muzzle (or antinodes) dampens the amplitude but will also decrease frequency. Both of which are desirable. Overall adding a tuning weight (adding non structural tunable mass) to a light barrel probably increases accuracy better than adding stiffness. Or at least is easier to account for and quantify.

I've only seen a few examples of load dev targets for carbon barrels but they seemed to change poi less than all steel barrels of similar weight that I have shot. Though much of that may be due to individual barrel quality as I have never shot a custom cut rifled sporter. So those barrels might have walked a little more due to stress properties or general differences in barrel quality.

You said you have shot both. Do you have any load dev targets I can take a peak at? I may have been been making assumptions as to the cause of an observation.

Again, I know a lot more about WHAT works than why........

There is a lot to know. Especially about something as dynamic as rifle accuracy. No one, including myself, is going to know all the what's or whys. That's why These forums are nice, we can try to fill in the gaps in our understanding with the quality experience and knowledge present on this board.