Quickload and/or GRT

[Dave M.]

Just curious as I’ve never used either of these, but I’m curious how people use them and what useful info can be taken from them? I’ve always worked up all my loads from scratch starting at a safe charge weight and finding nodes as I approach max charge weight. I’m just curious how people are using these tools and the potential value they offer.

Dave

 

[Dimner]

I used to use these programs to get all into the OBT type calculations. That kinda of load work up method can work, but I found it uses a lot more components and ends up with so many testing sessions.

Where I find these programs have the most impact is on the static specifications of a load. Using your observed velocity, actual measured case capacity, and other cartridge measurements to get a very useful estimation or pressure. Also you get case fill percentage and burn rate percentage. These last two help me predict if a load will have a tendency to be successful. Of course sometimes less than perfect case fill and/or non optimal burn percentage can still end up with a good load. However, I have experienced, more often than not, that being in the right range of burn and fill percentage equates to being on the right track for a good load.

All in all, QL and GRT are tools I use to help come up with a good start to my tuning followed by real world testing. If more than anything, it has helped me determine why a load may be a good tune. If there were no QL or GRT in this world, tuning would still be very possible, tons of people do it. I guess I'm saying it helps me tune with less components used overall.

 

[358WCF]

I've also never used either, but have saved a few of the printouts for things I have interest in. I'm in process of getting away from Alliant powders, mostly using Vv. There's damned little data for many older less popular cartridges (much of what I shoot). The safe start charge is the big question for many of these & I've considered getting QL. It just hasn't fit into the budget yet.

Thinking that I tried downloading GRT a few years back on the old computer & being the old dog that I am, couldn't get it running properly.

 

[tthomp302]

GRT is a really great tool and there’s some things you can do that get you fantastic loads very quickly. Reloading All Day offers an advanced load development class that teaches exactly what you need to use and calibrate GRT for the best results. It was 100% worth it for me.

 

[J_idaho]

I’ve been using grt for awhile. I’ve been just plugging in all my info and comparing it. It’s been accurate on the nodes I’ve tested. Takes some tweaking on starting pressure probably because of neck tension and primer choice. It’s not going to change the world and your still going to do all the testing anyways.

 

[AccelR8]

My use of GRT are mirrored by Dimner's second paragraph.

 

[6Creed73]

I use GRT and really like. I mostly use it to see the pressure curves and velocity to get an idea of what to expect from my load before I shoot it.

But I also really like the ability to do "what if" scenarios, like see what happens to velocity and pressure if I change seating depth or use a magnum primer instead of standard.

Being able to see the burnt powder percentage is also helpful. I shoot short barreled 300BLK and it's nice to see if burnt powder is really low, I will pivot and change the load up before wasting components.

 

[Dave M.]

I used to use these programs to get all into the OBT type calculations. That kinda of load work up method can work, but I found it uses a lot more components and ends up with so many testing sessions.

Where I find these programs have the most impact is on the static specifications of a load. Using your observed velocity, actual measured case capacity, and other cartridge measurements to get a very useful estimation or pressure. Also you get case fill percentage and burn rate percentage. These last two help me predict if a load will have a tendency to be successful. Of course sometimes less than perfect case fill and/or non optimal burn percentage can still end up with a good load. However, I have experienced, more often than not, that being in the right range of burn and fill percentage equates to being on the right track for a good load.

All in all, QL and GRT are tools I use to help come up with a good start to my tuning followed by real world testing. If more than anything, it has helped me determine why a load may be a good tune. If there were no QL or GRT in this world, tuning would still be very possible, tons of people do it. I guess I'm saying it helps me tune with less components used overall.

Can you expand on this: “Also you get case fill percentage and burn rate percentage. These last two help me predict if a load will have a tendency to be successful. Of course sometimes less than perfect case fill and/or non optimal burn”

 

[Dave M.]

I've also never used either, but have saved a few of the printouts for things I have interest in. I'm in process of getting away from Alliant powders, mostly using Vv. There's damned little data for many older less popular cartridges (much of what I shoot). The safe start charge is the big question for many of these & I've considered getting QL. It just hasn't fit into the budget yet.

Thinking that I tried downloading GRT a few years back on the old computer & being the old dog that I am, couldn't get it running properly.

I don’t even own a computer and my girlfriend has a rather old one. Lol.

 

[ZenArchery]

I shoot a lot of Wildcat calibers. Both GRT and QL help narrow down powder selection.

 

[rjh]

I have used both and find QL very useful when it is trued correctly. You must have accurate water volumes, and must true the powder to your real world velocities. Once that is done, it is very useful when paired with obt data. It is also imperative to enter correct temperature when truing velocities.

 

[Jager]

QuickLoad is probably my most-used computer program. Its biggest benefit to me is the ability to accurately understand how much chamber pressure a load is producing. It's been years since I've depended upon classic "pressure signs" - essentially metallic failure of the cartridge case itself - despite routinely loading at and around - and occasionally above - SAAMI max.

I find it very useful when trying to replicate a known load when moving to a different cartridge lot or headstamp, that has a different case volume. For example, a year ago I bought a case of Peterson 6 BR brass for making .30 BR. QL allowed me to very quickly understand what my match load using Lapua would need to be in the new Peterson cases. I tested it, of course. But I didn't have to. QL nailed it. I now rotate back and forth between batches of Lapua and Peterson brass.

I routinely use QL when changing component lots, especially powder, to understand if there's any variance between them; and, if so, how the load might need to be tweaked in order to marry up the different lots.

I also use QL to help understand how temperature differences might be affecting a rifle's tune. I've never used a powder that is completely temperature insensitive, and a load that works great in July will likely perform differently in January. Being able to quantify that difference and being able to understand exactly how much adjustment might be necessary to get a load back to square one is invaluable.

Modeling tools like QuickLoad and GRT require a good chronograph in order to unleash their magic. But if you do that they are transformative.

 

[Dimner]

Can you expand on this: “Also you get case fill percentage and burn rate percentage. These last two help me predict if a load will have a tendency to be successful. Of course sometimes less than perfect case fill and/or non optimal burn”

Sure thing. Note: I've never used these programs for magnum rifle or pistol loads. I have no idea if my observations hold true for those. Also, my experiences have mostly been for hitting 3/4 moa hunting loads. Confirmed at 100 and 200 yards. I've done a few at 1/2 MOA.

First Steps
One of the first things you do (or should do) when you start using this program is provide it with the actual measured H20 capacity of your fire formed brass in your chamber. With your actual case capacity measurements, you get far better predictions from the software.

Case fill
The software will use your case capacity, OAL, and other things to predict a case fill %. So you can see, for example that 30.1gr of H4198 will give me a fill percentage of 96.3%.

What I have noticed over the years is that the prevailing wisdom about case fill % is true. The closer you are to a full case, the better chance the load will be successful. Or maybe, I should say, the easier the load will be to tune. It's been my experience that for extruded powder, you want to be at least 85% full. For spherical powders, 90% or better seems to be a good spot. I have a feeling that these percentage guidelines will end up much tighter when it comes to ultra precise competition loads.

Powder Burn %
The software also provides a powder burn percentage. This data point provides you a percentage of how much of your original powder load has burned when your bullet exits the barrel. Further, you can consult the internal ballistics graph it gives you. It will allow you to see the burn % down the length of your barrel. So for example, you can see that 88% of the powder is burnt in the first inch or so.

I have noticed that this data point is also important to develop a successful load. In addition, on an anecdotal basis, I have noticed that less than efficient burn percentages contribute to faster barrel fouling. I don't know if it's carbon fouling, because if it doesn't burn, can it be carbon? However, have noticed that groups open up at a lower round count when the burn percentage is less than optimal. I personally like to keep the burn percentage 95% or higher. When you see 100% burn, then you would want to investigate where that 100% occurs in your barrel. Then contrast that knowledge with your velocity goals. You might be leaving some velocity on the table by using too fast of a powder

Applications in Load Dev/Tuning
If I were starting load dev for lets say a 6BRA....
I don't have an extra $700 on hand to go out and buy 16lbs of what powder everyone is using in competitions. So I have to get creative.

I would start with fireforming 10 pieces of brass to get my actual H20 case capacity and then I would 'run the numbers' with the 5-7 powders I have on hand that may possibly work with this cartridge. I'd choose 2-3 powders to do some initial velocity tests. I would pick them based on the software's predictions on Chamber Pressure, Case Fill %, and Powder burn rate and velocity. At this stage, take velocity predictions with a grain of salt. They are never on the mark until you get your chrono to measure actual velocities and back calculate some other variables.

So now I have 2-3 powders that seem to meet my goals. Time to test them for velocity.

 

[Dave M.]

I’ve been using grt for awhile. I’ve been just plugging in all my info and comparing it. It’s been accurate on the nodes I’ve tested. Takes some tweaking on starting pressure probably because of neck tension and primer choice. It’s not going to change the world and your still going to do all the testing anyways.

How is GRT accurate to predict nodes? Does it tell you where the “nodes” are somehow??

 

[Someone online]

Sure thing. Note: I've never used these programs for magnum rifle or pistol loads. I have no idea if my observations hold true for those. Also, my experiences have mostly been for hitting 3/4 moa hunting loads. Confirmed at 100 and 200 yards. I've done a few at 1/2 MOA.

First Steps
One of the first things you do (or should do) when you start using this program is provide it with the actual measured H20 capacity of your fire formed brass in your chamber. With your actual case capacity measurements, you get far better predictions from the software.

Case fill
The software will use your case capacity, OAL, and other things to predict a case fill %. So you can see, for example that 30.1gr of H4198 will give me a fill percentage of 96.3%.

What I have noticed over the years is that the prevailing wisdom about case fill % is true. The closer you are to a full case, the better chance the load will be successful. Or maybe, I should say, the easier the load will be to tune. It's been my experience that for extruded powder, you want to be at least 85% full. For spherical powders, 90% or better seems to be a good spot. I have a feeling that these percentage guidelines will end up much tighter when it comes to ultra precise competition loads.

Powder Burn %
The software also provides a powder burn percentage. This data point provides you a percentage of how much of your original powder load has burned when your bullet exits the barrel. Further, you can consult the internal ballistics graph it gives you. It will allow you to see the burn % down the length of your barrel. So for example, you can see that 88% of the powder is burnt in the first inch or so.

I have noticed that this data point is also important to develop a successful load. In addition, on an anecdotal basis, I have noticed that less than efficient burn percentages contribute to faster barrel fouling. I don't know if it's carbon fouling, because if it doesn't burn, can it be carbon? However, have noticed that groups open up at a lower round count when the burn percentage is less than optimal. I personally like to keep the burn percentage 95% or higher. When you see 100% burn, then you would want to investigate where that 100% occurs in your barrel. Then contrast that knowledge with your velocity goals. You might be leaving some velocity on the table by using too fast of a powder

Applications in Load Dev/Tuning
If I were starting load dev for lets say a 6BRA....
I don't have an extra $700 on hand to go out and buy 16lbs of what powder everyone is using in competitions. So I have to get creative.

I would start with fireforming 10 pieces of brass to get my actual H20 case capacity and then I would 'run the numbers' with the 5-7 powders I have on hand that may possibly work with this cartridge. I'd choose 2-3 powders to do some initial velocity tests. I would pick them based on the software's predictions on Chamber Pressure, Case Fill %, and Powder burn rate and velocity. At this stage, take velocity predictions with a grain of salt. They are never on the mark until you get your chrono to measure actual velocities and back calculate some other variables.

So now I have 2-3 powders that seem to meet my goals. Time to test them for velocity.

Sounds just like what I try to do.

 

[Dave M.]

Sure thing. Note: I've never used these programs for magnum rifle or pistol loads. I have no idea if my observations hold true for those. Also, my experiences have mostly been for hitting 3/4 moa hunting loads. Confirmed at 100 and 200 yards. I've done a few at 1/2 MOA.

First Steps
One of the first things you do (or should do) when you start using this program is provide it with the actual measured H20 capacity of your fire formed brass in your chamber. With your actual case capacity measurements, you get far better predictions from the software.

Case fill
The software will use your case capacity, OAL, and other things to predict a case fill %. So you can see, for example that 30.1gr of H4198 will give me a fill percentage of 96.3%.

What I have noticed over the years is that the prevailing wisdom about case fill % is true. The closer you are to a full case, the better chance the load will be successful. Or maybe, I should say, the easier the load will be to tune. It's been my experience that for extruded powder, you want to be at least 85% full. For spherical powders, 90% or better seems to be a good spot. I have a feeling that these percentage guidelines will end up much tighter when it comes to ultra precise competition loads.

Powder Burn %
The software also provides a powder burn percentage. This data point provides you a percentage of how much of your original powder load has burned when your bullet exits the barrel. Further, you can consult the internal ballistics graph it gives you. It will allow you to see the burn % down the length of your barrel. So for example, you can see that 88% of the powder is burnt in the first inch or so.

I have noticed that this data point is also important to develop a successful load. In addition, on an anecdotal basis, I have noticed that less than efficient burn percentages contribute to faster barrel fouling. I don't know if it's carbon fouling, because if it doesn't burn, can it be carbon? However, have noticed that groups open up at a lower round count when the burn percentage is less than optimal. I personally like to keep the burn percentage 95% or higher. When you see 100% burn, then you would want to investigate where that 100% occurs in your barrel. Then contrast that knowledge with your velocity goals. You might be leaving some velocity on the table by using too fast of a powder

Applications in Load Dev/Tuning
If I were starting load dev for lets say a 6BRA....
I don't have an extra $700 on hand to go out and buy 16lbs of what powder everyone is using in competitions. So I have to get creative.

I would start with fireforming 10 pieces of brass to get my actual H20 case capacity and then I would 'run the numbers' with the 5-7 powders I have on hand that may possibly work with this cartridge. I'd choose 2-3 powders to do some initial velocity tests. I would pick them based on the software's predictions on Chamber Pressure, Case Fill %, and Powder burn rate and velocity. At this stage, take velocity predictions with a grain of salt. They are never on the mark until you get your chrono to measure actual velocities and back calculate some other variables.

So now I have 2-3 powders that seem to meet my goals. Time to test them for velocity.

Great info. I’d love to learn how to use it. The engineer in me loves predictive programs that can produce accurate results without real world testing, like CFD for fluids and FEA for stresses under a given load scenario.

 

[RegionRat]

How is GRT accurate to predict nodes? Does it tell you where the “nodes” are somehow??

Neither one is predicting full dynamic nodes, just OBT times.

GRT and QL do not have a FEM or structural dynamics model of the gun.

To actually model well enough to predict external ballistic nodes at the target is way beyond the scope of programs like QL or GRT, but it does help those interested in the OBT theory and internal ballistics.

What is being calculated is the barrel time (Internal Ballistics theory) and it lists the possible OBT times (like Chris Long's theory for speed of sound in steel) for comparison. So the programs help since you don't have to go run a different spreadsheet for OBT times.

Something not mentioned yet in the discussions above, is what to do when you Wildcat or experiment with load recipes not listed anywhere else.

In other words, I use the GRT and QL models to plan Wildcats and explore new powders. If you play with case volumes and bullet weights, the programs will help model how powders will burn.

If you don't have anywhere else to get anecdotal advice, these programs are a good way to avoid the expense of ordering reamers and wasting barrels on ideas that don't have a good chance of working out.

They can also serve as a back-up load manual for recipes that don't exist, and/or estimate pressure for published recipes that don't list pressure or case fill.

It would only take you a few hours to get started with GRT or QL. GRT's creator passed away recently, but his friends are supporting his program well enough. GRT is free, but QL isn't.

If you are or were an engineer, you won't take very long to get up to speed on either one, but you will need a decent computer.... YMMV

 

[C_Ackley]

These programs are only as useful as the information you feed them. You must measure your bullet's actual length and weight, as well as your fired case's capacity in H20. Some powder models are a little funky and I don't like playing with those even when the chronograph differs.
The 44 Mag Redhawk-Only load I developed chronographed exactly where Quickload predicted it would within 5fps.

 

[JFrank]

These programs are only as useful as the information you feed them. You must measure your bullet's actual length and weight, as well as your fired case's capacity in H20. Some powder models are a little funky and I don't like playing with those even when the chronograph differs.
The 44 Mag Redhawk-Only load I developed chronographed exactly where Quickload predicted it would within 5fps.

Mentioned in post #13 under first steps..

 

[J_idaho]

How is GRT accurate to predict nodes? Does it tell you where the “nodes” are somehow??

Ya it shows you what powder charge for all available nodes. It doesn’t tell you how wide they are but maybe I’m just not able to read that part. I can post a pic later when I get to my laptop. Just by changing temp setting changes the node so the more info you have on the load the better. I’ve ran powder tests and you can see it will line up. I’m not sure how far the burn rate calibration works past the info you put in because of all the variables at play. Like powder burn out and pressure. It’s kinda fun to mess with.