I had read about GRT (Gordon’s Reloading Tool) before but I have QuickLoad and have been pleased with the results so I never really considered investing further. However after reading Boule’s post in the LeverRevolution thread. I figured I would check it out.
First of all, I didn’t realize it is free. Maybe this is because it’s still under development. So if anyone else is interested I would encourage you to download it and check it out. It may not be free forever.
Here is the link to the download. You do have to create an account before you can download the zip file. https://grtools.de/doku.php?id=en:doku:install
If you are already familiar with Quickload the main screen is a bit nicer looking. It looks different but overall the main parts are somewhat similar. There is a module to open the cartridge database and if necessary make modifications to the specs. They have a fairly comprehensive powder database and projectile database. The settings are all metric but you can easily change those to more familiar non-metric units through the context menus or simply clicking the small measure icon next to the specific field that you want to change.
Quickload Main Screen
GRT Main Screen
Like Quickload you grab the case, projectile and powder components from the drop down library tool. Unlike Quickload the output and graph curves update immediately with each change. No need to click the “apply and calc” button like QL.
There are quite a bit more tools that I briefly checked out, but I have not yet had the chance to fully examine. These three features that I did explore are not included in Quickload.
The Propellant Burn Rate Chart is pretty well organized and you are able to sort the list by Progressive Burn Rate, Brisance or a combined formula. They specifically note that these charts are GRT specific and may differ from other charts.
There is also a Parametric Powder Search Tool. I haven’t really messed around with it yet, but it appears that you type in the parameters that you desire for your load, and the program then pulls the powders which would perform similarly.
They also have an Optimal Barrel Time calculator. If you are not already familiar with OBT theories they rely on the physics calculations of the barrel harmonics and try to calculate the best “time” that the projectile should exit the barrel where it would be closest to the barrel axis. I ran the tool using a proven load and the result is pretty close to the charge that I use.
There are lots of other extras but I check those out later.
Like I mentioned this examination all started from @Squaregrouper’s post to determine if LeverRevolution powder is a good suitable substitute for H4350 in 6.5 Creedmoor loads. So the first thing I did was enter my my own personal 6.5 Creedmoor proven load using H4350 and compare it to LeverRevolution.
Here is the output for LeverRevolution
Here is the output for H4350
So according to GRT these two powders using the exact same load are a bit different the LR seems to be about 12,000 PSI higher than H4350 producing a muzzle velocity about 120fps faster. That’s pretty substantial.
This simple comparison however struck me as pretty strange because the MV reported by GRT was actually about 100fps faster than my QL data and also faster than my verified MV data which has been repeated over 400+ rounds.
So there seemed to be some differences between the two. I did find a few small differences between the case dimensions and the projectile dimensions. These were very small but I changed the GRT values to match my QL numbers. The MV changed but only slightly. Then I noticed what appeared to be quite a few differences between the powder parameters.
So after playing around with the GRT parameters I modidied each to match the default values from the QL database.
After making this change the two programs reported almost identical interior ballistic output.
Quickload calculates 2779 fps
Vs GRT which calculated 2772
So in this example when all of the parameters for GRT are tuned to match the exact parameters in QL they report similar (almost identical) output. So my first question is to try and understand why the powder database within GRT is different from QL. Since my real chrono data is closer to QL I have to assume that the GRT data is wrong (or at least not accurate for my own conditions).
I have quite a lot of verified loads in QL for .223/5.56 and 300BO. I’ll try to compare those side by side too. I’m interested to know if any other members have compared GRT to QL and their real world data, or who would be willing to do so and post here.
Just fyi. If the powder is not in Quickload, try GRT for a change. The two programs are not completely interchangable but often yield comparable results. Quickload is still curated but updates are slow, GRT is in development.
First of all, I didn’t realize it is free. Maybe this is because it’s still under development. So if anyone else is interested I would encourage you to download it and check it out. It may not be free forever.
Here is the link to the download. You do have to create an account before you can download the zip file. https://grtools.de/doku.php?id=en:doku:install
If you are already familiar with Quickload the main screen is a bit nicer looking. It looks different but overall the main parts are somewhat similar. There is a module to open the cartridge database and if necessary make modifications to the specs. They have a fairly comprehensive powder database and projectile database. The settings are all metric but you can easily change those to more familiar non-metric units through the context menus or simply clicking the small measure icon next to the specific field that you want to change.
Quickload Main Screen
GRT Main Screen
Like Quickload you grab the case, projectile and powder components from the drop down library tool. Unlike Quickload the output and graph curves update immediately with each change. No need to click the “apply and calc” button like QL.
There are quite a bit more tools that I briefly checked out, but I have not yet had the chance to fully examine. These three features that I did explore are not included in Quickload.
The Propellant Burn Rate Chart is pretty well organized and you are able to sort the list by Progressive Burn Rate, Brisance or a combined formula. They specifically note that these charts are GRT specific and may differ from other charts.
There is also a Parametric Powder Search Tool. I haven’t really messed around with it yet, but it appears that you type in the parameters that you desire for your load, and the program then pulls the powders which would perform similarly.
They also have an Optimal Barrel Time calculator. If you are not already familiar with OBT theories they rely on the physics calculations of the barrel harmonics and try to calculate the best “time” that the projectile should exit the barrel where it would be closest to the barrel axis. I ran the tool using a proven load and the result is pretty close to the charge that I use.
There are lots of other extras but I check those out later.
Like I mentioned this examination all started from @Squaregrouper’s post to determine if LeverRevolution powder is a good suitable substitute for H4350 in 6.5 Creedmoor loads. So the first thing I did was enter my my own personal 6.5 Creedmoor proven load using H4350 and compare it to LeverRevolution.
Here is the output for LeverRevolution
Here is the output for H4350
So according to GRT these two powders using the exact same load are a bit different the LR seems to be about 12,000 PSI higher than H4350 producing a muzzle velocity about 120fps faster. That’s pretty substantial.
This simple comparison however struck me as pretty strange because the MV reported by GRT was actually about 100fps faster than my QL data and also faster than my verified MV data which has been repeated over 400+ rounds.
So there seemed to be some differences between the two. I did find a few small differences between the case dimensions and the projectile dimensions. These were very small but I changed the GRT values to match my QL numbers. The MV changed but only slightly. Then I noticed what appeared to be quite a few differences between the powder parameters.
So after playing around with the GRT parameters I modidied each to match the default values from the QL database.
After making this change the two programs reported almost identical interior ballistic output.
Quickload calculates 2779 fps
Vs GRT which calculated 2772
So in this example when all of the parameters for GRT are tuned to match the exact parameters in QL they report similar (almost identical) output. So my first question is to try and understand why the powder database within GRT is different from QL. Since my real chrono data is closer to QL I have to assume that the GRT data is wrong (or at least not accurate for my own conditions).
I have quite a lot of verified loads in QL for .223/5.56 and 300BO. I’ll try to compare those side by side too. I’m interested to know if any other members have compared GRT to QL and their real world data, or who would be willing to do so and post here.