"Will Someone Do A Video Tutorial "GRT for Dummies?"

[markr6754]

This (Gordon's Reloading Tool) looks to be quite useful. However, there is very little information for a new user, at least not that I've been able to find.

Is there a secret society that produced a string of video tutorials, but I'm lacking the secret handshake to access them? Or is it that everyone has years of experience using QuickLoad and adapted rather easily to GRT?

To use an old submarine term...I'm looking for a "sea daddy". Anyone able/willing to help a guy out?

 

[LiveLife]

How about a video from the programmer himself, Gordon?



Tutorial Optimal Barrel Time with GRT

 

[uuolf]

Great program... I ran quickload for a while (and computer programming in general for 20 years...) It still took me a little time to acclamate my self... It's well worth your time investment... Good luck

 

[LiveLife]

Found this tutorial video and learned Gordon had passed away ... Hopefully the Open Source project will continue on but if you are concerned about not being able to download in the future, I would go ahead and at least download the program to be used later. (I am not a user of GRT but will download to use with Windows and Linux OS)

 

[markr6754]

How about a video from the programmer himself, Gordon?



Tutorial Optimal Barrel Time with GRT

I actually watched both of these videos before I downloaded it and opened it. They would be appropriately titled...GRT for master reloaders.

I'm looking for a much more basic run through.

 

[csjavi]

On the GRT page at https://grtools.de/ there is a link to join their Discord. That seems to be the place to learn and ask questions.

 

[Mr_Flintstone]

I actually watched both of these videos before I downloaded it and opened it. They would be appropriately titled...GRT for master reloaders.

I'm looking for a much more basic run through.

Some important things to note when using GRT.
1. Compact mode is more user friendly for beginners.
2. Take careful measurements of your case lengths, case volumes, and seating depths of your bullets you intend to load, and make sure you enter those values into GRT.
3. GRT tends to overestimate the velocity in many cases, but pressures tend to be fairly close; assuming you put everything in correctly.
4. Give yourself a little wiggle room when you calculate heavy loads. Remember that it is just a computer model, and actual pressures may vary.

I would suggest that you take a published load value for a cartridge that gives velocity and pressure (in PSI), and play around with getting your GRT values to match the max published data. Then alter the values to see how it matches for minimum values. Keep in mind that it probably won't match exactly, but should be fairly close.

 

[Howa 9700]

If I understand things correctly, both Gordons and Quickload are simulation programs based on Chris Long's Optimal Barrel Time theory, which was developed in part from observation that some load combinations seem to work well in a large number of similar guns. (My pet load question).

http://www.the-long-family.com/OBT_paper.htm

Looked into QL and Gordons and quickly concluded both exceeded my level of interest and ability, so dropped it. But as I understand the premise, loads are developed using some characteristics of the gun (barrel length, etc), but not any one gun in particular. The rest comes from characteristics and combinations of individual powders, bullets, etc.

But if that is the case, it circles back to question of pet loads does it not? For a 308 win with 22 inch barrel, the programs can predict an optimum combination of powder, bullet, bullet seating depth? How is that not the same as a pet load? Especially if it works in a lot of 308 rifles with 22 inch barrels?

 

[Howa 9700]

BTW, there may be many fallacies using GRT or QL, but one that comes to mind to me is both seem to be based on a benchmark or "standard" for each powder. I'm not sure that is a valid assumption. Recently had occasion to pull down some loads using IMR4350, loaded a few years back. Saved powder and put a different charge of same powder back in the cases it came from. This was thru a powder measure but weighed each charge and was trickling up. Had more cases to load, so when pull down powder ran out, resumed loading with new bottle / different lot of IMR4350. Weight of drop from same volume measure changed well over 1/2 of a grain. Concluded the two would not be compatible, so stopped with new loads.

But have concluded that unless the math done to develop the loads on GRT or QL is from same powder lot as I have (it is not), results may vary, and by a lot.

 

[Bearded Phil]

There's a folder that downloads when you download the zip file that contains the program called "doku". In it is a manual in a variety of languages, give that a read.

 

[Mr_Flintstone]

This (Gordon's Reloading Tool) looks to be quite useful. However, there is very little information for a new user, at least not that I've been able to find.

Is there a secret society that produced a string of video tutorials, but I'm lacking the secret handshake to access them? Or is it that everyone has years of experience using QuickLoad and adapted rather easily to GRT?

To use an old submarine term...I'm looking for a "sea daddy". Anyone able/willing to help a guy out?

In the absence of a basic video, just post your questions here. If it’s something I can answer, I will give it my best effort, and I’m sure that others will reply as well.

In some ways, that’s better than a video because you can specifically ask what you don’t know.

 

[markr6754]

There's a folder that downloads when you download the zip file that contains the program called "doku". In it is a manual in a variety of languages, give that a read.

I completely missed this. It's certainly worth a read, since it most likely answers the majority of my questions.

@Mr_Flintstone thanks for the okay. I'll be sure to do that. Appreciate the openness.

 

[Howa 9700]

If anyone has the program, here would be a question / test.

Assume I have a 6mm Rem with 22" barrel, and I want to load 100 grain Nosler partition bullets using h4831sc powder. I have R-P once fired and new resized cases. What else needs to be known to give me an optimal load? What info would I get?

 

[westernrover]

BTW, there may be many fallacies using GRT or QL, but one that comes to mind to me is both seem to be based on a benchmark or "standard" for each powder. I'm not sure that is a valid assumption. Recently had occasion to pull down some loads using IMR4350, loaded a few years back. Saved powder and put a different charge of same powder back in the cases it came from. This was thru a powder measure but weighed each charge and was trickling up. Had more cases to load, so when pull down powder ran out, resumed loading with new bottle / different lot of IMR4350. Weight of drop from same volume measure changed well over 1/2 of a grain. Concluded the two would not be compatible, so stopped with new loads.

But have concluded that unless the math done to develop the loads on GRT or QL is from same powder lot as I have (it is not), results may vary, and by a lot.

I develop my own models in Quickload. The powder that's in there is just a starting point, and they're good ones. I can definitely see for example that IMR4227 is going to overfill my case before I can get enough pressure, whereas W231 is going to leave a lot of empty case space. I can definitely use the pre-configured powders to get in the ballpark with respect to pressure, case capacity, and velocity with a given barrel length. It's not realistic to think the model in Quickload is going to predict everything with precision with no further input. I'm going to have to shoot and get my own data. Then I'm going to have to tweak the model in Quickload to match what I'm seeing in reality. If there is a difference in powder lots, or with what primers I'm using, or my particular brand of brass's internal capacity, besides the atmospheric conditions where I'm shooting, then that's all going to have to be adjusted for. It's not practical to expect that data to come preloaded into the software. How would the authors know? Once I adjust the model in the software for my real-world conditions and parameters, then it becomes increasingly valuable -- more than just a starting point. I really appreciate the ability to use the model to explore "what if's"... what's a different seating depth going to do to pressure? Do I need to add or take away powder to adjust? How will a different bullet length affect the load? How much velocity will I lose if I use a shorter barrel? If I want to match the velocity of one load with another load using a slower powder at a lower pressure, what charge weight do I start with? Then I go and test it and get more data. I record that data and then when I have those same questions again in the future, I have both the software model and my real-world results to help answer it.

 

[higgite]

Some important things to note when using GRT.
.
.
3. GRT tends to overestimate the velocity in many cases, but pressures tend to be fairly close; assuming you put everything in correctly.

I'm not doubting your statement but am curious to know how you arrived at your conclusion that pressures tend to be fairly close. Thanks.

 

[Bearded Phil]

I completely missed this. It's certainly worth a read, since it most likely answers the majority of my questions.

It's the best place to start for sure. I found a lot of the program to be intuitive and I've never used Quickload but everybody is different. I'm still learning some of the finer points in GRT myself. Best of luck and stay safe!

 

[Mr_Flintstone]

I'm not doubting your statement but am curious to know how you arrived at your conclusion that pressures tend to be fairly close. Thanks.

I’m not saying in all cases, but the loads I’ve matched up against Hodgdon show pressures that are pretty close.

Edit…. I mainly use this to develop starting loads or verify data posted on the internet. I’d never trust any simulation to give me a safe max load without a work up.

 

[markr6754]

So a fellow forum member @bfalcon00 did me a solid last night, and we did a Zoom conference where many of my questions re: GRT were answered, and more. Along with the suggestion of @Mr_Flintstone to make up some samples from published load data I'm a bit more prepared to venture into the joys of load modeling.

In particular, we used the 6mm ARC load I was working on, and showed me the critical areas of focus/concern...exactly what I was looking for in my quest for knowledge.

I know that a model is just that...but as a load development starting point with powders in "the range" but without published data...I'm ready to step gently.

Thanks to everyone that offered help, advice, and suggestions. Best forum, for sure!

 

[uuolf]

If anyone has the program, here would be a question / test.

Assume I have a 6mm Rem with 22" barrel, and I want to load 100 grain Nosler partition bullets using h4831sc powder. I have R-P once fired and new resized cases. What else needs to be known to give me an optimal load? What info would I get?

Great info, +1 for above... In either program you must have the exact measurements for the brass... Brand and firings don't matter as much (if at all) IMHO.. (you have to measure length / H2O capacity... and did I mention they have to be exact measurements)... And exact measurements for the bullet being used plus the OAL of the finished cartridge... All of these figures give the app the info to accurately calculate internal volume once a bullet has been seated... These are critical for the app to calculate pressures... Some would also say you need to have your actual chamber measurements... those affect the pressure also... I generally use the suggested chamber drawing/measurement though and that seems to work for me... "most" of the time... One thing I note is that I use the app to "understand" what changing each item does to the pressure... And only use the actual data output as part of a larger picture (I compare all data to different load manuals and info when I begin to "ladder" a load from min. to max.)... The app is great but it is for those who understand the handloading process fully... Hand loading is awesome... But it's one of a few hobbies that can be harmful to your health (or others around you) if you're not careful...

 

[Mr_Flintstone]

I’d like to add a side note here for casual adventure seekers looking for maximum velocity. You can get into trouble really easily by using default values for everything and pushing powder volumes up to the red line.

I have made comparisons on some loads between default values and what I have developed with carefully measured case volumes, bullet measurements, seating depths, and powder volumes; and while I was confident that my developed loads were safe and reliable, if I had used default values I would have been several thousand PSI above max with my components.

Another side note is to pay attention to the the powders. Many of them have been tested over a wider range of loads and have higher calibration values than others. If you are using a powder with a lower calibration measure, then be sure to start on the low end and ladder test.