Which barrel profile would act stiffer?

[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.

 

[INTJ]

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.

I could not disagree more. The "WHAT" is the set of actions that most consistently result in success.

The "WHY" is more of a nice to know and can be helpful, but it is not the priority. This principle is evident in most everything, and the examples of tasks being performed to a very high level of expertise without the practitioner knowing completely WHY are legion. In fact, that is so much the norm that it defies logic and common sense to think otherwise.

I trained many students to fly jets. A pilot doesn't need to know WHY using small inputs on the controls result in a more precise position when flying 3' fingertip on the wing. However, if a pilot doesn't know that is WHAT works, they will never be able to fly precisely or even safely as a wingman.

Trumpet players are not exactly sure WHY solid air support and a high tongue arch allows playing high notes easier (that is hotly debated), but they know that is WHAT works.

You don't have to understand WHY touching the black wire and the white wire at the same time on a live circuit will shock you, but you do need to know that is WHAT will happen.

While theory (the WHY) is nice and of value, actual results (the WHAT) always trump theory. The actual results are what validates the theory, and if the results don't match the theory the theory is wrong. It doesn't matter how good a theory is, if it doesn't work it isn't valid.

Those that try to fully understand the WHY before doing will always lose to those who learn WHAT and then go do it. I tell you that as someone who has successfully flown jets, has played very high notes on trumpet in concerts, and has shot multiple 1000 yd screamer groups. My success isn't that I have a complete understanding of WHY, my success is because of WHAT I have done.

And while I reject argument from authority, when the shooters that beat me all do things the same way, then it's logical to think their approach is something to try. And when I try it and figure out how to do it, and then start shooting smaller groups and higher scores, then I have validated their method......whether I fully understand the WHY or not.

 

[garandman]

I could not disagree more.

Well, I disagree with you. Especially your training pilots example. *Also* knowing the why of aeronautics is FAR better than "Do this cuz I said so." That approach will get a pilot killed when things don't go as planned. Understanding the why of how planes fly will help the pilot improvise in emergencies. Yours is the argument from authority "Do this cuz I said so." That's a playbook to work out of. Yours tells ppl WHAT to think. And that's necesary. But mine is the argument from science, logic and technology. Lift, air density, up/down drafts, air pockets, prevailing winds, etc etc "Here's WHY planes fly, now think for your yourself when the fit hits the shan, and the playbook didn't work."

Same with guns. Knowing the "why" helps the individual figger out if the recommended action will work for his unique set of variables.

Meh. To each his own. I'm always gonna wanna know the why. I don't feel badly if you disgaree.

 

[darkangel_r2]

What works gives direction for areas of study, experimentation, and improvement. Figuring out why stuff works is how we get innovation in our industry.

If we only care about the what works best at the time we would all be using extremely well crafted atlatls.

If we only care why things work we would probably still be hungry in the cave arguing whether the atlatl or the shepherds sling is better.

We should appreciate each other on here for what we bring to the table.

As a way to get this back on topic I added a weight calculator to the excel file and will update the op in a bit with the new file.

OP too old to edit. I will start another in the future specifically about barrel design and include more relevant information on that one.

 

[INTJ]

Well, I disagree with you. Especially your training pilots example. *Also* knowing the why of aeronautics is FAR better than "Do this cuz I said so." That approach will get a pilot killed when things don't go as planned. Understanding the why of how planes fly will help the pilot improvise in emergencies. Yours is the argument from authority "Do this cuz I said so." That's a playbook to work out of. Yours tells ppl WHAT to think. And that's necesary. But mine is the argument from science, logic and technology. Lift, air density, up/down drafts, air pockets, prevailing winds, etc etc "Here's WHY planes fly, now think for your yourself when the fit hits the shan, and the playbook didn't work."

Same with guns. Knowing the "why" helps the individual figger out if the recommended action will work for his unique set of variables.

Meh. To each his own. I'm always gonna wanna know the why. I don't feel badly if you disgaree.

What gets a pilot killed is not knowing WHAT to do and when to do it. Good pilots will have some idea of the WHY and are always trying to lean more about the WHY, but the WHAT will always show the way.

I shut down engines 17 times over my USAF career. I also had many other malfunctions. I wasn't sure WHY I had dual runaway trim--which creates control forces to heavy to control, but instead of theorizing WHY I took action, disconnected the trim system, and safely brought the place back. I was never sure exactly WHY I got an engine fire light, but I knew WHAT to do to safely deal with it.

We never know the complete why. The problem is the WHY is an endless hole that is never fully resolved. The more we DO, the more data points we have to help better understand the WHY. But again, the key is in WHAT to do.

Trying to fully understand the WHY first is putting the cart before the horse and will greatly slow down our progress.

You might be an INTP. That is the personality type that focuses on theory over results. I am an INTJ and while I do value theory, the most important issue to me is this simple question "does it work?" To me the theory is just a starting point to start actual testing and doing. I suspect that for you a perfect theory is the goal.

This disagreement on WHY vs WHAT is almost a textbook example of the differences between INTPs and INTJs. So we will never agree.