Gathering Data for Powder Model Development - Gordon's Reloading Tool

[RickKr]

I am shooting Alliant Reloader 25 in a Weatherby 257 Magnum. I would like to do some modeling of my loads in Gordon's Reloading Tool, but there is no powder model for it. There is a process for submitting data for powder model development (even realizing Gordon passed away and powder model development is stopped or severely slowed). It requires data from 2 calibers, 2 bullet weights and 2 charge levels (min. & max), according to info on GRT.

I have the Wby 257 and can shoot the necessary loads, but do not have any other calibers for which there are adequate load data to meet the input data requirements. I have a 30-06 Springfield but can only locate one bullet wt and one charge wt for it (Alliant data site - have at least 6 major load manuals and none have any loads for the 30-06). I do not have the 200 gr bullet for it either, but that can be solved fairly easily). Are there safe and reasonable options for filling the missing data requirements? Using a heavier bullet (eg. 220 gr.) and working up a load? I know there are circumstances where it isn't safe to use certain powders (particularly magnum powders) outside of published data ranges (although I think I've seen admonitions only about going below a certain charge wt for a given bullet rather than going up), so am loath to go there blind. And given that I have lighter 30 caliber bullets (180, 190 gr.), any options for them in this context?

Rick

 

[divingin]

Appears (on initial reading - this may be totally wrong for your project) that it's done through the GRT Labs Plugin. Read up in the help section under "Team", and GRT Labs Basics.

 

[RickKr]

Appears (on initial reading - this may be totally wrong for your project) that it's done through the GRT Labs Plugin. Read up in the help section under "Team", and GRT Labs Basics.

It think it is exactly what I was pursuing (until I went for Quickload, see below). I was in the initial stage, that of figuring out what data I needed to collect and how to get it, in order to submit, hence my questions. I hadn't gotten to the GRT Labs Plugin stage, but was aware of it. I was also in the process of porting the GRT Labs Basic info to my computer so I could use it more effectively. The graphic images are a bit small on the Discord interface and while they can be enlarged, I like having stuff offline to work with more directly (old school, still prefer hardcopy materials for studying).

In the meantime, it came to my attention that Quickload has RL25 in it already and when considering that I'd have to buy at least two boxes of bullets I don't really want for the shooting I do and use up a box of a friend's 300 WSM factory rounds (found enough load data for 300 WSM, so makes moot my questions about the 30-06) to get the brass to work up the loads with RL25, I would have spent at least half of what QL costs. Coupled with the fact that GRT powder development is essentially stalled due to Gordon's passing, it is totally uncertain when or if a new model for RL25 would be forthcoming even once I submitted the appropriate data, etc. So, I bit the bullet and paid for QL. It will take a bit for shipping, but I wouldn't get to working up those loads for a couple weeks anyway.

 

[Fast14riot]

It think it is exactly what I was pursuing (until I went for Quickload, see below). I was in the initial stage, that of figuring out what data I needed to collect and how to get it, in order to submit, hence my questions. I hadn't gotten to the GRT Labs Plugin stage, but was aware of it. I was also in the process of porting the GRT Labs Basic info to my computer so I could use it more effectively. The graphic images are a bit small on the Discord interface and while they can be enlarged, I like having stuff offline to work with more directly (old school, still prefer hardcopy materials for studying).

In the meantime, it came to my attention that Quickload has RL25 in it already and when considering that I'd have to buy at least two boxes of bullets I don't really want for the shooting I do and use up a box of a friend's 300 WSM factory rounds (found enough load data for 300 WSM, so makes moot my questions about the 30-06) to get the brass to work up the loads with RL25, I would have spent at least half of what QL costs. Coupled with the fact that GRT powder development is essentially stalled due to Gordon's passing, it is totally uncertain when or if a new model for RL25 would be forthcoming even once I submitted the appropriate data, etc. So, I bit the bullet and paid for QL. It will take a bit for shipping, but I wouldn't get to working up those loads for a couple weeks anyway.

When I started with GRT it didn't have data for RL23, I got all the relevant info from someone with QL and plugged those in. The model came very close to actual measured velocities and charge weights.

 

[RickKr]

When I started with GRT it didn't have data for RL23, I got all the relevant info from someone with QL and plugged those in. The model came very close to actual measured velocities and charge weights.

When was this? Recently, since January? And what info (parameters, settings, etc.) were you able to get out of QL that would suffice for a powder model in GRT? I have purchased QL but it hasn't arrived. I have printed the QL manual and will study it. It may be apparent once I do, but it would be interesting to know what parameters to focus on.

 

[dstoenner]

Just so everybody is aware, GRT is frozen right now. Gordon passed away and his wife has not found anybody to replace him yet in the development. So no bug fixes nor new powders. They did release a version that set the timeout in like 2040 for this version.

I personally find it is fine and solid for what powders I use and bullets/cases. So I am happy to plod along I do hope this gets going again for opur communities sake.

David

 

[Fast14riot]

When was this? Recently, since January? And what info (parameters, settings, etc.) were you able to get out of QL that would suffice for a powder model in GRT? I have purchased QL but it hasn't arrived. I have printed the QL manual and will study it. It may be apparent once I do, but it would be interesting to know what parameters to focus on.

Here is some info I got back in 2019 for this:

what I have found is that in QL when you pull up the powder editor, "factor b" is what equates to "z2" *AFTER* it is converted in GRTools: you edit the powder profile in GRTools and enter the "Factor b" value and when you press ENTER it gets converted to a value that can be used by the GRTools algorithm - i.e., I input "1.5349" from the QL 'Factor b' into the GRTool editor and when I press ENTER it converts to 0.8374.
The bulk density of 0.930 g per cubic centimeter translates to pcd of 930 kg per cubic metre
so for H4831SC:
Qex = 3870
k = 1.2324
Ba = 0.4301
a0 = 0.44
z1 = 0.49
z2 = 0.8374
pc = 1550
pcd = 930

RL-23 would be a similar exercise. I do not have any empirical data for the temperature coefficients at this time

 

[RickKr]

Here is some info I got back in 2019 for this:

what I have found is that in QL when you pull up the powder editor, "factor b" is what equates to "z2" *AFTER* it is converted in GRTools: you edit the powder profile in GRTools and enter the "Factor b" value and when you press ENTER it gets converted to a value that can be used by the GRTools algorithm - i.e., I input "1.5349" from the QL 'Factor b' into the GRTool editor and when I press ENTER it converts to 0.8374.
The bulk density of 0.930 g per cubic centimeter translates to pcd of 930 kg per cubic metre
so for H4831SC:
Qex = 3870
k = 1.2324
Ba = 0.4301
a0 = 0.44
z1 = 0.49
z2 = 0.8374
pc = 1550
pcd = 930

RL-23 would be a similar exercise. I do not have any empirical data for the temperature coefficients at this time

Very interesting. I'll have to revisit this and perhaps PM you after I receive QL and have some time to familiarize. However, it is possible that I won't feel the need to use GRT much any longer.

I do not have a clue what any of those other factors are, so there is a lot for me to learn. The k and Ba factors are the ones modeled by the OBT function in GRT, I think, but I still don't know what they mean.

Thanks,

Rick

 

[DHall_37]

Just so everybody is aware, GRT is frozen right now. Gordon passed away and his wife has not found anybody to replace him yet in the development. So no bug fixes nor new powders. They did release a version that set the timeout in like 2040 for this version.

I personally find it is fine and solid for what powders I use and bullets/cases. So I am happy to plod along I do hope this gets going again for opur communities sake.

David

I wouldn't say its frozen, it's still very usable and there is a discord group that has moderators/ engineers working directly with the program. They aren't taking any new data currently, but they are maintaining the program and helping others with issues and concerns.

 

[RickKr]

I wouldn't say its frozen, it's still very usable and there is a discord group that has moderators/ engineers working directly with the program. They aren't taking any new data currently, but they are maintaining the program and helping others with issues and concerns.

Maybe not frozen, but about as fast as molasses on the shady side of an iglo, at least as far as powder model development goes. Certainly, GRT is still a very usable and useful tool with existing powder models and there is a very active support community. I have enjoyed using it and have received valuable support from the Discord group.

 

[nobrien22]

I finally downloaded and began using GRT... and after trying to use some of the advanced features to contribute to the online database, it seems to me that 1. No one is tending to it, or it isn't a very high priority for whoever is. 2. This will deter any further participation from the greater shooting community, which will effectively kill the project.

Does anyone else find it interesting that such a great tool was suddenly stopped in its tracks? Keep in mind there are more people than ever who are buying guns, and I'm quite sure, reloading, too. So, with more people shooting and interested in shooting, isn't it strange that a tool like GRT is suddenly frozen?

I think it's pretty clear what has happened. Western governments (like Germany, GB, and the U.S.) do not want the public to have access to a program like GRT. Why? Well, a couple of reasons. It's an excellent piece of software ( the UI is far superior to Quickload, with their circa 1992 Windows interface, and the GRT database *was* juuuust starting to reach a critical mass to be something that most reloaders would want to use) for spreading knowledge about internal and external ballistics. It's freely available online. It's not easily controllable if all you need is an internet connection to have up to date ballistics information on every cartridge, both commercial and wildcats, freely available. I have serious doubts about Gordon's death being a legitimate reason behind the program stalling. Consider for a moment that QL is strictly controlled and cannot be shipped to Ukraine, Russia, etc, etc. What do you know, then, that GRT, which is based in Germany, is suddenly, coinciding with the war in Ukraine, is now dead in the water.

It's a travesty what our supposed representatives have done to our ability to simply work together and share information in order to further our individual ability to enjoy our sport, without having to spend a lot of money for an out of date and subpar product.

I will be writing my representative, and I encourage every person who enjoys the sport of shooting, their 2nd amendment rights (for those in the U.S.), and the ability to reload, to do the same with their respective representatives, both local and on a federal level.

 

[95GTSpeedDemon]

does the OBT function change the powder burn characteristics or just re-estimates the pressure based off the powder data already there with the new actual fps?

 

[RegionRat]

No, it is the other way around, meaning the bullet's time-position in the barrel is affected by pressure, but those OBT calculations have no affect on pressure.

The pressure calculation is independent of OBT theory. The code calculates those OBT exit times based on the speed of sound in the barrel steel and the length of the barrel.

 

[95GTSpeedDemon]

10-4. guess that means i need to get a strain gauge for a known load/pressure and capture that on my oscilloscope so i know what max pressure looks like. wonder if thats possible?

 

[RegionRat]

wonder if thats possible?

Not following? Of course it is possible.
This has been done for longer than we have been alive.

It is easy to apply the gage and rig up the bridge balance and such, but the calibration is tricky for hobbyists.
You can easily enough get the time base plot, but calibrating the magnitude scale is the real challenge.

If you have the background with strain gage and recording fast events, then this isn't hard. The calibration will take some extra work since you can only come so close without real lab work.

Not long ago, a small outfit was selling a turnkey package with the circuits, software, and supplies to do this for home use, but they quit.

 

[95GTSpeedDemon]

Not following? Of course it is possible.
This has been done for longer than we have been alive.

It is easy to apply the gage and rig up the bridge balance and such, but the calibration is tricky for hobbyists.
You can easily enough get the time base plot, but calibrating the magnitude scale is the real challenge.

If you have the background with strain gage and recording fast events, then this isn't hard. The calibration will take some extra work since you can only come so close without real lab work.

Not long ago, a small outfit was selling a turnkey package with the circuits, software, and supplies to do this for home use, but they quit.

I havent used a strain gauge, but i use various pressure & Piezo sensors to find automotive issues.

I agree the calibration will be an issue. Do you know of good litature that simpletons can comprehend. Someone had a pressure trace for sale awhile back but i didnt want to invest in it since the company shut down.

 

[RegionRat]

The Pressure Trace is the best way without opening up a can of worms.

They charge real money for the engineering texts used to teach these topics and the only alternatives I can think of are to buy training materials from the companies that sell strain gage training kits.

https://www.tecquipment.com/assets/documents/datasheets/SM1009-Strain-Gauge-Datasheet.pdf

 

[95GTSpeedDemon]

how do most wild catters do it? are they waiting until they blow a primer or make it crater something nasty, or hard bolt lift?

 

[jfjohn77]

GitHub - zen/grt_databases: Gordons Reloading Tool Databases - Calibers, Projectiles and Powders

Gordons Reloading Tool Databases - Calibers, Projectiles and Powders - zen/grt_databases

github.com

 

[jfjohn77]

I finally downloaded and began using GRT... and after trying to use some of the advanced features to contribute to the online database, it seems to me that 1. No one is tending to it, or it isn't a very high priority for whoever is. 2. This will deter any further participation from the greater shooting community, which will effectively kill the project.

Does anyone else find it interesting that such a great tool was suddenly stopped in its tracks? Keep in mind there are more people than ever who are buying guns, and I'm quite sure, reloading, too. So, with more people shooting and interested in shooting, isn't it strange that a tool like GRT is suddenly frozen?

I think it's pretty clear what has happened. Western governments (like Germany, GB, and the U.S.) do not want the public to have access to a program like GRT. Why? Well, a couple of reasons. It's an excellent piece of software ( the UI is far superior to Quickload, with their circa 1992 Windows interface, and the GRT database *was* juuuust starting to reach a critical mass to be something that most reloaders would want to use) for spreading knowledge about internal and external ballistics. It's freely available online. It's not easily controllable if all you need is an internet connection to have up to date ballistics information on every cartridge, both commercial and wildcats, freely available. I have serious doubts about Gordon's death being a legitimate reason behind the program stalling. Consider for a moment that QL is strictly controlled and cannot be shipped to Ukraine, Russia, etc, etc. What do you know, then, that GRT, which is based in Germany, is suddenly, coinciding with the war in Ukraine, is now dead in the water.

It's a travesty what our supposed representatives have done to our ability to simply work together and share information in order to further our individual ability to enjoy our sport, without having to spend a lot of money for an out of date and subpar product.

I will be writing my representative, and I encourage every person who enjoys the sport of shooting, their 2nd amendment rights (for those in the U.S.), and the ability to reload, to do the same with their respective representatives, both local and on a federal level.

^^^^^^
I cannot agree more!
At 73 years of age, I've only been using this program less than a week, very impressed! For me it seems easy, I just wish there was an organized forum or group where ideas and information could exchanged or discussed. And there may be, I just haven't found it, or don't know where to look.
Still not real sure exactly how to import the files I located and posted above. Could definitely use some help there!