Combining barrel whip and OBT

[Nick.T]

So I love to research things and I have come to a bit of a weird wall. I am just starting to get into rifle shooting but I've been reloading and shooting pistols for a few years now. I've come into the theories of barrel whip and OBT and I have a question for someone far more experienced than I am. Is there any way to calculate barrel whip? From what I have seen accuracy nodes can be found outside of what is suggested by the OBT calculations. That would imply that a second set of options (what I can only conclude to be caused by barrel whip existing at a different point from the expansion waves of OBT) exists outside of OBT. If you could somehow calculate what load would reach the barrel crown in accordance with the whip of the barrel based on barrel stiffness then you could compare the two numbers and potentially have a barrel made for you that would position the whip at the optimal point while also meeting the OBT expectations. The problem is I haven't found a way to calculate the barrel whip. Does anyone know if this exists? I can't be the only person to have looked at creating a unified theory

 

[mram10]

Barrel whip test without firing a shot? A simple ladder test aka creighton audit method will find it with minimal shots being fired, but I’m not aware of a calculator that accurately computes it.

 

[Nick.T]

That will determine the nodes for a given barrel but I may have not phrased my question right. I'm looking to see if a calculation can be made that will determine accuracy nodes that could be found in a ladder test and you could manipulate barrel length and thickness in the calculation. Basically you would have an equation that uses barrel length and thickness, to mathematically find the optimal muzzle velocity to hit a creighton node. Then you manipulate the thickness in the equation to match up to an OBT node. You then take that thickness to a barrel manufacturer and tell them the length and thickness you want. And use the load calculated by OBT for a theoretical "perfect combination"

 

[Titan]

That will determine the nodes for a given barrel but I may have not phrased my question right. I'm looking to see if a calculation can be made that will determine accuracy nodes that could be found in a ladder test and you could manipulate barrel length and thickness in the calculation. Basically you would have an equation that uses barrel length and thickness, to mathematically find the optimal muzzle velocity to hit a creighton node. Then you manipulate the thickness in the equation to match up to an OBT node. You then take that thickness to a barrel manufacturer and tell them the length and thickness you want. And use the load calculated by OBT for a theoretical "perfect combination"

Read this it references a few attempts to model barrel movement. http://www.geoffrey-kolbe.com/articles/rimfire_accuracy/tuning_a_barrel.htm
Edit: one of the attempts from the article using a simulation to model the effect of a barrel tuner http://www.varmintal.com/apres.htm

 

[mikecr]

Some barrel whip is tied to stock flex. Then you have various recoil movements affecting muzzle position.
Once I attempted to measure muzzle movement with a laser mic and high speed DAS. It was a dismal failure, but brought to my attention that measure & predictions, as a gun is used in the field, would cost huge money/time to resolve..

 

[Webster]

So I love to research things and I have come to a bit of a weird wall. I am just starting to get into rifle shooting but I've been reloading and shooting pistols for a few years now. I've come into the theories of barrel whip and OBT and I have a question for someone far more experienced than I am. Is there any way to calculate barrel whip? From what I have seen accuracy nodes can be found outside of what is suggested by the OBT calculations. That would imply that a second set of options (what I can only conclude to be caused by barrel whip existing at a different point from the expansion waves of OBT) exists outside of OBT. If you could somehow calculate what load would reach the barrel crown in accordance with the whip of the barrel based on barrel stiffness then you could compare the two numbers and potentially have a barrel made for you that would position the whip at the optimal point while also meeting the OBT expectations. The problem is I haven't found a way to calculate the barrel whip. Does anyone know if this exists? I can't be the only person to have looked at creating a unified theory

Sounds like a job for NASA a super computer and big bucks. Too many variables to account for. Just how you torque the action screws could change everything. Just shoot the rifle at a target.

 

[Nick.T]

I figured it would be a little to hard to calculate. I was hoping that if you could figure out the changes necessary to the OBT calculation then it wouldn't be a huge step. It was more of a theory in my head than anything else.

That's a shame mikecr that you couldn't get any meaningful data from it but sometimes that's how it goes

 

[mikecr]

What matters is why things do or do not work. So it can be meaningful either way.

 

[Hoodoo]

http://riflebarrels.com/a-look-at-the-rigidity-of-benchrest-barrels/