Gordons reloading tool

Just having a play with this and have a couple of questions.


Under projectile it asks for two diameters if selecting a boat tail, obviously one is the calibre but what is the other measurement?

The other question is I selected ADI 2208 as the powder and in the ADI manual it says I can go from 34gr to 36.5gr max for 22-250 and 55gr pills, but the tool gives me a warning of over pressure if I choose even a moderate 35gr powder charge.

So how accurate are these tools and do I need to take heed when the manual says I will be ok?

Thanks

Unless you're using something really oddball you should be able to pick the specs out of the projectile library.

In the top line(of the projectile section) is the magnifying glass - click on that and find your bullet. It should provide you with all the values you need. These are usually spot on, though as with everything it never hurts to do a quick sanity check!

From memory the dimensions it requires are the diameter of the projectile at the bottom end of the boattail, and the length of the boattail i.e. from the base to where the projectile becomes full diameter.

It has different warning levels, one is when you are approaching max pressure and a different one when it's over. ALWAYS compare loads from Quickload or GRT with another source and ofcourse work up. Cheers

as a quick aside, just downloaded this but cant seem to get it to start up.
It seems to be more of a file than a program
What have i done wrong?

you have to look for the "application" file (should have a big black dot beside it) and right click it to make it run. Then make a link to it. Cheers

cheers
ill give that a go

@Happy Jack - I just threw together a quick model using default case capacity, ADI 2208 and a variety of 55g projectiles. At 36.5 grains some get close to the maximum for 22-250 (58740psi) but most are below max comfortably.

What parameters have you set in your model?
Have you changed case capacity?
Have you changed cartridge length (overall length)?
Have you fiddled with the combustion rate of the powder or initial pressure?

The beauty of GRT is that once the variables are understood changes can be seen easily - bearing in mind as @Tentman says, it's a model and should always be regarded as ONE more source of information and NEVER the last word!

As a precautionary note, I suggested earlier to do a sanity/safety check on the inputs you can check. I discovered a projectile that had incorrect information in the library that lead me towards a potentially dangerous situation - and odd results that weren't making sense. Once I corrected the projectile specs the modelling reflected my actual chronographed results much more closely.

Another useful thing to know is that most of the ADI powders that are repackaged and sold under the Hodgdon label have much better profiles (more real life results/more data points) under the Hodgdon listing in GRT. The coloured bars in the powder library indicate the volume of information used to create the model, so in this case check out the Hodgdon Varget listing (this is AR2208).

And in relation to your first question about the two diameters required for the boattail part of a projectile - diameter A is there to specify the diameter where the boattail finishes. Usually this is just the bullet diameter, but in the case of a rebated boat tail it should be a bit less than bullet diameter (this has a tiny but measurable effect on case capacity with the projectile seated - which is displayed as the combustion chamber output).

Thanks everyone especially @Steelisreal for explaing things in detail.

I had just gone with the std settings for cartridge ect but now you have explained things hopefully I can input my actual data.

There I was expecting a picture of a bored out nip pourer
I feel let down!

I have found this tool to be within 10 fps of labradar results on the few charges I have chrono'd.

Once the Chrono arrives from this forum and the blasted wind dies away I can test my loads and see how close the speed is to what GRT says. Getting my head around it with a little bit of help and comparing what it said on a box of factory ammo to what GRT was telling me I was able to figure out the results.

I just download this again for another go at it, I had the beta version a couple of years ago and didn't like it.
This time I found it much better than Quickload especially tweaking the powder variables to much actual Chrono velocity's.
Watching this video help me get started very quickly.
Needless to say I won't be updating my version of Quickload.

https://www.youtube.com/watch?v=XxDJ...dZR-NA&index=2

Quote:

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Originally Posted by winaa

I just download this again for another go at it, I had the beta version a couple of years ago and didn't like it.
This time I found it much better than Quickload especially tweaking the powder variables to much actual Chrono velocity's.
Watching this video help me get started very quickly.
Needless to say I won't be updating my version of Quickload.

https://www.youtube.com/watch?v=XxDJVROdyxc&list=TLPQMjYwMTIwMjFJ7z_RdZR-NA&index=2

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Where did you find the info on "tweaking" powder variables ??

He might mean when you make your own table based on readings then submit it to GRT they look at it and alter redefine the parameters ...that seems to happen when they do an update.
I provided them with some more info on the 308 HBC optimus 155 grn and they updated it.
That took less than a week, I dont know if QL would make changes based on Joe Blogs info.

Quote:

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Originally Posted by Tentman

Where did you find the info on "tweaking" powder variables ??

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@Tentman
About a 1/3 of the way through the video above, you put your measured velocity in the measurement's tab and then go to OBT and hit calculate it bring up the tweaked K and Ba to enter in the main window.
You may need to watch the video a couple of time's the SA accent is pretty strong

Quote:

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Originally Posted by johnd

He might mean when you make your own table based on readings then submit it to GRT they look at it and alter redefine the parameters ...that seems to happen when they do an update.
I provided them with some more info on the 308 HBC optimus 155 grn and they updated it.
That took less than a week, I dont know if QL would make changes based on Joe Blogs info.

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@johnd
Submitting a load is a good idea I did 2 today using ADI 2208. The more us Kiwi's and Ozy's submit the better the calibration.
But no you can tweak the load using the OBT Tab after have input your measured velocity as shown in the video.

Quote:

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Originally Posted by johnd

He might mean when you make your own table based on readings then submit it to GRT they look at it and alter redefine the parameters ...that seems to happen when they do an update.
I provided them with some more info on the 308 HBC optimus 155 grn and they updated it.
That took less than a week, I dont know if QL would make changes based on Joe Blogs info.

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QuickLoad don't even respond to emails seeking support as I found out.

Quote:

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Originally Posted by winaa

@Tentman
About a 1/3 of the way through the video above, you put your measured velocity in the measurement's tab and then go to OBT and hit calculate it bring up the tweaked K and Ba to enter in the main window.
You may need to watch the video a couple of time's the SA accent is pretty strong

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Thanks for that @winaa
I have been playing with GRT, and some of my loads initially had pressure warnings but velocity was higher than measured. I had run the OBT function and entered measured velocity (which then showed lower pressure), but I didn't know what if any values I could or should change in the original file to make things work.
On a related note, changing from AR2208 to Varget did bring velocity closer to measured.

@winaa I did a download and got the latest version today, then played with my seating depth, I do like how responsive the data is. The warnings are a lot better than past models, where a whole batch of charges would show as "overpressure" now only those that are actually "hot" will show up.
I have found the OBT function pretty good ... but then I have only used it in .308 where I find almost any powder gives good accuracy ( god bless the 308:D )

Thanks, I gained a lot for that vid.

But now - Can anyone explain why all of FClass John, Eric Cortina and Bolt Action Reloading have noted small drops in MV as they seat projectiles deeper (i.e. more jump) whereas GRT and Q/L predict the velocity increases when seating depth is reduced?? Thanks

Only the difference in real world testing as opposed to theory perhaps?

Have downloaded the video to watch when I have more time. Thanks