Quickload and Nodes

[wbanz]

Here in New Zealand powder is in short supply and you have to take what you can get. I acquired Quickload to provide a shortcut to changing powders with minimum risk and fuss. However I am grappling a bit with the software/data and comments/advice in the forums.
I am familiar with the concept of Nodes and have always loaded to the top or bottom of barrel vibration, I am new to the concept of "loading to node 5 or 6" (for example) and am researching this now. Many of the forum comments mention QT nodes. I cannot find anything in QL that refers to Nodes.
Any pointers would be appreciated.

 

[FeMan]

I have never found anything in QL relating to nodes. The closest thing I have found is using a barrel harmonic calculator I found on the internet some years ago and comparing the "Barrel Tome - Pmax to exit" in QL to what that calculator predicted. That had limited and sporadic success so I gave up on it.

One of the primary things that I use in QL modeling to help sort through what may work best is Pmax vs Z1. Generally you want the point of conversion of powder solid to gas (Z1) at or before the Pmax. Z1 following Pmax can lead to combustion instability and erratic accuracy.

I also found that I had to change the Weighting Factors on many cartridges to get things to line up with measured results (velocity). Tuning the Ba with powder lots is often required for me a s well.

I am still fine tuning my loads at 1k to get the optimal configuration. QL only gets me so far..

I hope you have better luck with components soon.

 

[CharlieNC]

Google Chris Long Optimal Barrel Time (OBT). It provides a chart and calculations based on barrel length, and then use adjustments in quick load barrel time to find the barrel time which matches. Many find this approach works well to id the node, or at least very close to that found by shooting, which matches my experience. Some think the principle is flawed.

 

[PhilKeil]

There is a optimal barrel time calculator available that assists.

You will have to search for it. You can also find a chart and a excel calculator at Chris Longs site.
As Fe man mentions it is not perfect and not always spot on accurate. 1 thing to keep in mind is the values saved in the program for the powders, bullets, cases etc are either the samples they measured or what is being reported by the manufacturer of the component. Some values are averages and your supplies will be different. Example my son is working on a rifle project now. the h2o capacity stored for his cartridge and what he actually measured in twice fired cases is plus 5 grains of H2o. That is a big difference.
Same thing with powders, basic reloading skills say when changing any lot/component you reduce the charge and work up. There is lot to lot variation. Mass produced bullets are giving me fits right now and need to be sorted to give the best results. So you can not depend on what is stored within the program. It is merely a guide/starting place.
I shoot all testing over a chrono and tweak the values to align as what FE man mentions. once done things tend to work out well and become predictable. QL becomes a excellent tool to model and test changes. I think it provides a start and you can weed out what has the potential to work but you still have to put the work and components into it.

 

[choprzrul]

I have never found anything in QL relating to nodes. The closest thing I have found is using a barrel harmonic calculator I found on the internet some years ago and comparing the "Barrel Tome - Pmax to exit" in QL to what that calculator predicted. That had limited and sporadic success so I gave up on it.

One of the primary things that I use in QL modeling to help sort through what may work best is Pmax vs Z1. Generally you want the point of conversion of powder solid to gas (Z1) at or before the Pmax. Z1 following Pmax can lead to combustion instability and erratic accuracy.

I also found that I had to change the Weighting Factors on many cartridges to get things to line up with measured results (velocity). Tuning the Ba with powder lots is often required for me a s well.

I am still fine tuning my loads at 1k to get the optimal configuration. QL only gets me so far..

I hope you have better luck with components soon.

I want to make sure I understand what you are saying here.....Z1 (0.625 in my snip below) occurs before 10% PMax to Muzzle (1.098ms). It just feels like I'm missing something here or I'm using the wrong data....

 

[Straightshooter1]

Here in New Zealand powder is in short supply and you have to take what you can get. I acquired Quickload to provide a shortcut to changing powders with minimum risk and fuss. However I am grappling a bit with the software/data and comments/advice in the forums.
I am familiar with the concept of Nodes and have always loaded to the top or bottom of barrel vibration, I am new to the concept of "loading to node 5 or 6" (for example) and am researching this now. Many of the forum comments mention QT nodes. I cannot find anything in QL that refers to Nodes.
Any pointers would be appreciated.

If you're very technical and like reading such things, then this here may be of interest to you (if you haven't already seen it): http://www.the-long-family.com/OBT_paper.htm

I use QuickLoad's barrel time calculation to identify a node and when changing powder's to match a good load I'll use that along with matching QL's pressure calculations for the different powder. While it's NOT an exact science or an exact match, I get very close results on my .308 loads that only require some slight tweaking to get what I'm hoping for.

As shown above, QL has a node calculator, which is essentially the same as other's I've seen . . . like this:

 

[FeMan]

I want to make sure I understand what you are saying here.....Z1 (0.625 in my snip below) occurs before 10% PMax to Muzzle (1.098ms). It just feels like I'm missing something here or I'm using the wrong data....

View attachment 1251967

In your example, the Z1 occurs around 0.5 ms and Pmax occurs around 0.4 (see the graph in the bottom left). That is telling me that the powder charge is still converting solid to gas after Pmax and is a sign that the powder is a on the slow side. You are still on the light side of the pressure and the Z1 will slide closer to the Pmax as you increase charge weight. I doubt it will get far enough to get there though.

The Pmax is a function of the load, so I think the highlighted values are different things. I think the Z1 you have highlighted is a characteristic of the powder itself and not the load. I am not 100% sure though. I am used to plotting the Chamber Pressure graph by inches of barrel instead of travel time. I don't think it maters though. I was referring to the relative position of the two lines (Z1 and Pmax). No matter how you graph it, before is before and after is after.

Hope that helps explain what I was talking about.

 

[jepp2]

There is a optimal barrel time calculator available that assists.

How do you access that?

 

[PhilKeil]

Here is a link to it below.

QuickLOAD OBT Tool

Calculates optimum barrel time. The picture tells it all. http://www.weatherbyrifler.com/Download/Pics/OBT.png

castboolits.gunloads.com

If you go to link below for chris long aka techshooter and scroll to quick links is a link tot the excl version of the same thing

Optimal Barrel Time Concept

www.the-long-family.com

hope that helps

 

[BCBRAD]

I want to make sure I understand what you are saying here.....Z1 (0.625 in my snip below) occurs before 10% PMax to Muzzle (1.098ms). It just feels like I'm missing something here or I'm using the wrong data....

View attachment 1251967

Your shot start pressure is at the default of 3 626 psi, is your jump 0.247"

 

[Lkwebb]

Here in New Zealand powder is in short supply and you have to take what you can get. I acquired Quickload to provide a shortcut to changing powders with minimum risk and fuss. However I am grappling a bit with the software/data and comments/advice in the forums.
I am familiar with the concept of Nodes and have always loaded to the top or bottom of barrel vibration, I am new to the concept of "loading to node 5 or 6" (for example) and am researching this now. Many of the forum comments mention QT nodes. I cannot find anything in QL that refers to Nodes.
Any pointers would be appreciated.

Here is the chart for barrel lengths for obt

 

[Lkwebb]

If you're very technical and like reading such things, then this here may be of interest to you (if you haven't already seen it): http://www.the-long-family.com/OBT_paper.htm

I use QuickLoad's barrel time calculation to identify a node and when changing powder's to match a good load I'll use that along with matching QL's pressure calculations for the different powder. While it's NOT an exact science or an exact match, I get very close results on my .308 loads that only require some slight tweaking to get what I'm hoping for.

As shown above, QL has a node calculator, which is essentially the same as other's I've seen . . . like this:

View attachment 1252002

I've got quickload but I haven't found the node calculator..

 

[SeabeeKen]

The obt calculator is an add on that you down load. You can just download the chart from the long family site and print out.
ive found that when the z1 and pmax are stacked on top of each other, that this is the perfect burn rate for the cartridge as input.
after you fine tune ql, you use the barrel time in conjunction with the obt chart to find the node. Assuming ql is not perfect, I start with the charge that hits the proper barrel time and then work out in both directions in .2 gr increments higher and lower if pressure allows to find the precise node. This works well for me, often starting with a load that shoots .5 and sometimes .7. It makes it easier and faster to find the node thereby saving time and components. It isn’t easy to get all the variables to line up. Ba, wf, start pressure, etc. many don’t use the temp feature for powder but it is very helpful