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Old June 9, 2019, 10:11 PM   #26
higgite
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Quote:
Originally Posted by Aguila Blanca
After all that, I'm still not able to enter Winchester 231 into the propellant database. With the data provided by Uncle Nick, I'm still missing the following, and GRT won't allow me to save without entering values for all the parameters (which is a good thing):

Isentropic exponent (k)
Transition limit (z2)
Bulk density
W231 values from Quickload V.3.8:
Isentropic exponent (k) = 1.222 cp/cv (QL calls it Ratio of Specific Heats)
Bulk density = 0.696 g/cm^3 = 696 kg/m^3 in GRT speak

I couldn't find a value in QL for Transition limit (z2).

Last edited by higgite; June 9, 2019 at 10:57 PM.
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Old June 9, 2019, 11:09 PM   #27
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Thanks. Did you by any chance try GRT using those numbers to see if it would accept the propellant without a value for z2?
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Old June 10, 2019, 12:06 AM   #28
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Quote:
Originally Posted by jmorris View Post
Look at table 1 in your link and compare it to the burn rates here

https://www.hodgdon.com/wp-content/u...rate-color.pdf

And here

https://loaddata.com/Article/BurnRat...-Chart-NEW/159

With the exception of long shot and the table one puts N320 and TG equal in recoil (same as I have found, though N320 is cleaner), they are listed in the order of their burn rates.
And other burn rate charts place Longshot in a more 'appropriate' place than the Hodgdon chart. And many of those charts also have a good match with the recoil data as well, with some exceptions, too.

The 'problem' is that there is no single universally accepted measure for placing powders on burn rate charts, otherwise they would all agree.

After staring at burn rate charts for years, and loading gazillions of differ loads, It's clear that rankings for a given company are pretty solid, such as ranks for only Vihtavuori or ranks for only Winchester. But rankings that compare Vihtavuori versus Winchester versus Ramshot, etc. are not agreed on, so I try not to take them too seriously, other than to say the burn rates are similar or not so similar.

And I suspect that rankings of closely related powders change or shift a bit when comparing different cartridges where case volume differs and some powders might act a little different in particular calibers. Here, too, I don't fret over it much and just follow the published data.

Also, lot number difference of the same powder can have a big effect with some powders. I've seen this personally.

At least when measuring recoil, the results are consistent with the physics, in this case charge weight. There might be some exceptions here too with closely related powders, since the other stuff that's added to powders (fillers, flash suppressors, copper fouling retardants, etc.) can change the other stuff to explosive ratio and affect its weight. Although I suspect they would be minor contributions to the overall effect, and this appears to be the case because the powder weight is pretty good at predicting recoil force and Ransom Rest movement. And maybe the Ransom Rest is a better measure because it's not stuck with trying to match a formula. It doesn't know how much it's supposed to move; it's movement is dictated by the applied force. More force = more movement.
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Old June 10, 2019, 11:48 AM   #29
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Quote:
Thanks. Did you by any chance try GRT using those numbers to see if it would accept the propellant without a value for z2?
It wouldn't accept a new propellant without a value other than zero for z2. I made one up just to see if it would accept it and it did.

On another note, I compared the GRT curve for N320 to the QL curve and their slopes don't match. I don't know how significant that is or is not, but they do give different resultant MVs by 3-4% for hypothetical pistol loads.
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Old June 10, 2019, 12:36 PM   #30
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The slopes and shapes are close enough to be considered a match within lot tolerances. GRT seems to have tried to further refine the model by including a second inflection of the vivacity curve where the first derivative of the curve function drops below zero by some predetermined amount. By a little eyeballing and applying a little math I suggest you try using 0.74 for z2 for 231/HP38 and see if that isn't pretty darn close.

Back before American industry succeeding in lobbying government to let them keep more information proprietary, the MSDS information included other names for the same powders. Winchester 231 and HP38 were both listed as OBP231 and the source for both as St. Marks in the 2007-2009 era MSDS sheets. So they are definitely the same powder.

Also, note that QL has different densities for 231 (0.696) and HP38 (0.770). This is from sampling different lots. A look at Western's site for Ramshot powders reveals bulk densities can differ by 11.2% between lots for some, while others hold that spread down to about 4.4%. Presumably, the rest of the industry lives with similar irregularities, so finding a couple of different numbers, it makes the most sense to me to use the average of the two, which is 0.733 g/cc.

Hodgdon and Western and Alliant are all distributors. Hodgdon took over IMR and Western distributing as well as distributing ADI powders here under their own name designations, and Western took over Accurate, Ramshot, and Norma, among smokeless powders. Shooter's World just distributes Lovex powders as far as I know, but with their own naming system as Hodgdon does with ADI powders. They all order their powders made by plants around the world and either package it from drums themselves or have it packaged by the maker. They have basic powder types and their required burn rate and bulk density tolerances and I believe that's all they need to order new lots made when they run low.
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Old June 10, 2019, 01:47 PM   #31
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Quote:
Originally Posted by Unclenick
Back before American industry succeeding in lobbying government to let them keep more information proprietary, the MSDS information included other names for the same powders. Winchester 231 and HP38 were both listed as OBP231 and the source for both as St. Marks in the 2007-2009 era MSDS sheets. So they are definitely the same powder.
You've been at this reloading stuff a lot longer than I have, and in far greater depth. I just load a few pistol rounds and I'm happy if they go Bang and make holes in the paper. I have picked up the Win 231 and HP-38 are the same powder. Do you happen to know if any of the other Winchester powders are the same as other Hodgdon powders? That could be useful to me down the road if my reloading horizons expand. I used to buy Winchester 231 from the shop at my range and I paid his asking price to support a local shop (the owner of which is a friend). He has since dropped reloading supplies. If I have to shop the errornet for powder, it would help to know what other powders are direct substututes rather than close alternates.
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Old June 10, 2019, 02:30 PM   #32
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For handgun powders, I don't recall any other 'crossovers'.
For rifle powders, there are a few.

And it goes beyond just Hodgdon/Winchester/IMR. Plenty of powders have been sold under different labels, and few people were any wiser.
Accurate 1680, for example, was a repackaged Lovex powder until the early 2000s - and the Lovex powder, itself, a canister grade version of Explosia D063; which was also packaged and sold by Norma at one time. (I ran out of logical punctuation there. The semi-colon seemed like the best compromise...)

I do not recall which powder it is, but Western Powders is supposed to be selling Explosia D063 under one of their labels, now. ...And variants of it, D063-01 and D063-02, are being sold as Lovex / Shooter's World SBR-SOCOM and Lovex / Shooter's World BLACKOUT, respectively.

One powder. At least half a dozen labels. Several minor variants.

It is not, at all, uncommon.

Quote:
The 'problem' is that there is no single universally accepted measure for placing powders on burn rate charts, otherwise they would all agree.
That's exactly why I can't figure out why there's still any argument about burn rate charts.
They're all different - and have to be, since they use different methods for "ranking" - and we all know it.
Can't we all just agree that different burn rate charts are ... different?
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Old June 10, 2019, 03:33 PM   #33
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I've seen any number of comparative powder burn rate charts, and I can't recall a single one that had any actual data. They all just list a bunch of powders, from fast to slow. No indication of how much faster any powder is than the one immediately below it, or the one ten spots below it.

Look at the Hodgdon chart. HP-38 is #28 on the chart, Winchester 231 is #29. Anyone not knowing they are the same powder could logically conclude that HP-38 is faster than 231 -- after all, they aren't both listed as #28 [Tie], and then the numbers skip to #30 as most listings involving a tie are done. Is the jump from those two to #30 a 5% difference, a 10% difference, or a 25% difference? Or is it only 1% or 2%, which could be reversed if another batch were tested? Who knows -- you certainly can't tell from the charts, because the listings aren't quantified.

So, regardless of whose chart you look at, IMHO it should be used as a gross indicator, not a scientific data source.
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Old June 10, 2019, 04:46 PM   #34
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Quote:
Originally Posted by Unclenick
The slopes and shapes are close enough to be considered a match within lot tolerances. GRT seems to have tried to further refine the model by including a second inflection of the vivacity curve where the first derivative of the curve function drops below zero by some predetermined amount. By a little eyeballing and applying a little math I suggest you try using 0.74 for z2 for 231/HP38 and see if that isn't pretty darn close.
Changing the value of z2 in GRT doesn’t alter the shape of the burn rate curve. It does move the spot on the curve where z2 kicks in and it does change the output data.

FWIW, I used W231 data from QL to create a W231 entry in GRT. QL doesn’t have a z2 data point, so I used z2 = 0.74 in GRT as suggested by Unclenick. QL does have an internally calculated “Factor b” which GRT doesn’t have. I have no idea what significance that holds.

With identical cartridge dimensions and barrel length in both programs, the results still differed. Projectile was Hornady 115gr, FMJ/RN, 35557. Powder charge was 4.2gr of W231. The following results are in the format GRT/QL.

Pmax = 25783/22709 psi
Muzzle P = 3438/3864 psi
Propellant burnt = 100.0/99.52 %
MV = 1084/1024 fps
Ballistic eff = 36.8/32.8 %

Last edited by higgite; June 10, 2019 at 04:52 PM.
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Old June 10, 2019, 10:01 PM   #35
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Quote:
Originally Posted by higgite
With identical cartridge dimensions and barrel length in both programs, the results still differed. Projectile was Hornady 115gr, FMJ/RN, 35557. Powder charge was 4.2gr of W231. The following results are in the format GRT/QL.

Pmax = 25783/22709 psi
Muzzle P = 3438/3864 psi
Propellant burnt = 100.0/99.52 %
MV = 1084/1024 fps
Ballistic eff = 36.8/32.8 %
Those numbers work out to percentage variations of (respectively):
12%
12%
.48%
5.5%
11%

I don't know just what that means, but if a 5% variation is acceptable for estimation software, then most of their numbers differ by more than what's acceptable.

But -- what if GRT is right and QL is wrong? I sure don't know enough to guess. I'll be interested in plugging those Win 231 values into the program and comparing its results to my real world results.
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Old June 11, 2019, 03:36 PM   #36
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QuickLOAD models the vivacity curve as two separate curves that meet at a point. In reality, that point would be rounded, so the peak number is a little high. Ba and B are coefficients that describe the curvature of the first and second curves, the rising rate of gas evolution and the falling rate of gas evolution. GRT uses three curve slopes, one before the peak, Ba, like QuickLOAD does, for the increasing rate of gas evolution, and two curves that look like circular segments, one between z1 and z2 on the horizontal scale, rather than a single parabolic or perhaps inverse square function (can't tell clearly from the graphs) as QuickLOAD appears to do for falling rate of gas evolution. So GRT is using a different progressivity powder characterization. I have no reason to know one is better than the other as both are intended to model by approximation and not to be exact answers.

Exact answers are tricky. Not even measurements get you there. Here, from the older SAAMI standards, are examples of how well-calibrated pressure measurement works out without reference loads to adjust the scaling to. Note the Standard Deviation of velocity is much lower than for the peak pressure measurements.



So, understanding a 10% disagreement in pressure from the measured value might actually be just fine, I looked at the model again. As you increase z2, the pressure holds up better (you get higher muzzle pressure) but it occurs when the powder is closer to consumed. I am still thinking through the ramifications of this. I went back to QuickLOAD and put the vivacity v. Ba values into Excel and graphed them. There, the second inflection clearly occurred later than my first look had put it, at about z2=0.9. So I put that new value into the GRT HP38 model. I also averaged some the other properties QL had for HP38 and 231. That all resulted in good enough agreement between the two programs.

Code:
Case water overflow capacity of 14.0 grains water
Hornady 115 FMJ
101.6 mm barrel (4")
COL 1.125"

          QL      GRT    Hodgdon Measured for Gold Dot 115-grain bullet
Peak psi 31657   32199     28100
Muzz psi  4580    4570
MV   fps  1164    1179      1167
BE    %     35      37
Powder Properties (GRT allows publication of screenshots in the license agreement)

Attached Images
File Type: gif Carbine and 357 Ammo Test.gif (30.1 KB, 286 views)
File Type: gif GRT HP38 231.gif (59.2 KB, 125 views)
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Old June 11, 2019, 05:05 PM   #37
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Unclenick,
Attached are two vivacity curves from GRT for W231 with different values for z2, 0.5 and 0.9. I don't see any difference in the shape or slope of the curves when z2 changes. z2=0.9 added a tail on the very end of the curve that z=0.5 doesn't have, but other than that the curve didn't change. However, the calculated Pmaxes and MVs did change, so z2 obviously makes a difference, but knowing why it makes a difference is beyond my pay grade.

Edit: If you can make the images appear in my post, please do.

Just hover over the links that appeared at the bottom of the page, right click, and from them menu click to copy the link location. Then click on the little postcard icon at the top and paste that copied link into it. If you don't see the icon you can manually tell it the link is to an image by typing an opening and closing image tag and putting the link between them. It looks like this:

[IMG]https://thefiringline.com/forums/attachment.php?attachmentid=109791&stc=1&d=1560368496[/IMG]

Which produces this:


or

[IMG]https://thefiringline.com/forums/attachment.php?attachmentid=109792&stc=1&d=1560368496[/IMG]

Which produces this:
Attached Images
File Type: png Screen Shot 2019-06-11 at 4.35.06 PM.png (58.9 KB, 98 views)
File Type: png Screen Shot 2019-06-11 at 4.30.30 PM.png (58.8 KB, 96 views)

Last edited by higgite; June 11, 2019 at 05:29 PM.
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Old June 11, 2019, 07:38 PM   #38
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A question - The manufacturer screenshots are so small I can't see all the inputs.
Speed is impacted by many more factors than just the components of the round of ammunition. In rifles especially, barrel length is a factor as are the lands and groves and twists of them. Then there's whether the bullet is crimped. Different brass has different capacities which can differ from brass to brass by several grains - so the amount of space within the brass is a factor that impacts combustion pressures. Does the software account for barrel length, bullet crimp, and brass manufacturer/headstamp? I've also seen numerous discussions on the impact of primer choice as well. Is primer choice in the software?
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Old June 11, 2019, 07:52 PM   #39
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Barrel length, bore, land and groove dimensions, polygonal bore dimensions, etc., are variables that can be massaged in both QL and GRT. I haven't seen any inputs for crimping, primer brand or brass headstamps. Brass internal volume is an input variable. You can download GRT for free and see exactly what is in it.
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Old June 11, 2019, 11:31 PM   #40
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Quote:
Originally Posted by higgite
Barrel length, bore, land and groove dimensions, polygonal bore dimensions, etc., are variables that can be massaged in both QL and GRT. I haven't seen any inputs for crimping, primer brand or brass headstamps. Brass internal volume is an input variable. You can download GRT for free and see exactly what is in it.
In fact, the program includes a caution about relying on standard volume for the cartridge, and asks you to confirm if you wish to proceed using the default volume rather than entering your own.
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Old June 12, 2019, 02:20 AM   #41
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AB i believe ww296 and h110 are also the same powder. Others can confirm. Thats the only other duplicate i am aware of besides 231/hp38.
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Old June 12, 2019, 11:24 AM   #42
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As long as I use standard bullets and powders and stick to manufacturers recipes do I really need something like this? I know some of you shoot some pretty exotic cartridges where load data is scarce or non existent but for someone like me that colors inside the lines would this be helpful ?
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Old June 12, 2019, 11:38 AM   #43
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Quote:
Originally Posted by hounddawg
As long as I use standard bullets and powders and stick to manufacturers recipes do I really need something like this?
I don't shoot exotic loads, but I do use QL to estimate new loads (new bullets, different COL, etc.) by comparing with known loads that I have chronographed. GRT is free. Try it and see if you think it's worthwhile for you.
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Old June 12, 2019, 01:28 PM   #44
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honestly Higgite after thinking on it I doubt if I would find any practical use for the info it provides. Sounds like a good low cost alternative to QL however. For me reloading hypotheticals are not something I will ever be concerned with. I only care about the results on the target and the chrono. Sounds like a neat tool for those who do have a use for it though
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Old June 12, 2019, 02:55 PM   #45
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Higgite,

I put your images in your post along with instructions for two ways to do it. If you look at your curves you will see they are not identical. When you move z2 to 0.9, notice the green tale has a much steeper drop and ends near zero on the vertical Ba scale, whereas when it is at 0.5 the curve ends at 1.0 on the Ba scale, indicating it is still burning and producing gas. In other words, it hasn't made all its gas yet, which is why the muzzle pressure is higher for the 0.9 value because all the gas has been made and is pressurizing the bore at the moment the bullet exits.


Aguilla Blanca,

Since the MSDS's change after 2009, I don't have the equivalent information on the newer powders, but here's the table of older ones I got from the MSDS sheets for that date and earlier:

Code:
Powders from 2009 MSDS sheets (some newer MSDS sheets lack the powder name information due to
changes in MSDS requirement regulations).

Note that bulk grade versions have wider burn rate specs and can vary significantly from the
canister grades, which are controlled for burn rate by blending with held back fast or slow 
lots, as needed to adjust them to within ±3% of their nominal burn rates.

     Canister      | Bulk Grade |       Canister         | Canister |      Canister        |
      Grade        |            |        Grade           |  Grade   |       Grade          |
                   | St. Marks  |                        |          |                      |
     Hodgdon       | Mil & OEM  |      Winchester        | Thales   |        IMR           |
___________________|__Numbers___|________________________|__(ADI)___|______________________|_
                   |            |                        |          |                      |
HP-38--------------|-- OBP231 --|- 231 ------------------|----------|----------------------|-
                   |   OBP124   |  AALite (WFL)          |          |                      |
Titewad            |   OBP132   |                        |          |                      |
Tightgroup --------|-- OBP242 --|------------------------|----------|----------------------|-
                   |   OBP465   |  Super-Handicap (WSH)  |          |                      |
Longshot           |   OBP473   |                        |          |                      |
Lil' Gun ----------|-- OBP516 --|------------------------|----------|----------------------|-
Hybrid 100V        |   SHP771   |                        |          |                      |
                   |   SMP224   |  AutoComp              |          |                      |
-------------------|--- WAA90 --|- WST ------------------|----------|----------------------|-
H110               |    WC296   |  296                   |          |                      |
HS-6               |    WC540   |  540                   |          |                      |
HS-7               |    WC571   |  571                   |          |                      |
-------------------|--- WC748 --|- 748 ------------------|----------|----------------------|-
H414               |    WC760   |  760                   |          |                      |
H335               |    WC844   |                        |          |                      |
BL-C(2)------------|--- WC846 --|------------------------|----------|----------------------|-
H380               |    WC852   |                        |          |                      |
US869              |    WC869   |                        |          |                      |
-------------------|-- WMR780 --|- Supreme 780 ----------|----------|----------------------|-
                   |   WXC170   |  WSF                   |          |                      |
Clays              |            |                        |  AS30N   |                      |
International Clays|------------|------------------------|- AS50N --|----------------------|-
Universal Clays    |            |                        |  AP70N   |                      |
H4227              |            |                        |  AR2205  |IMR 4227 second source|
H4198 -------------|------------|------------------------|- AR2207 -|----------------------|-
                   |            |                        |   BM1    |                      |
H322               |            |                        |  AR2219  |                      |
Benchmark          |            |                        |   BM2    |                      |
-------------------|------------|------------------------|- AR2210 -|- IMR 8208 XBR -------|-
H4895              |            |                        |  AR2206H |                      |
Varget             |            |                        |  AR2208  |                      |
H4350 -------------|------------|------------------------|- AR2209 -|----------------------|-
H4831              |            |                        |  AR2213  |                      |
H4831SC            |            |                        | AR2213SC |                      |
H1000 -------------|------------|------------------------|- AR2217 -|----------------------|-
Retumbo            |            |                        |  AR2225  |                      |
H50BMG             |            |                        |  AR2218  |                      |
-------------------|------------|------------------------|- AR2215 -|IMR 4198 second source|
                   |            |                        |  AS25BP  |IMR Trail Boss        |
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Old June 12, 2019, 09:28 PM   #46
higgite
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Unclenick,

Thanks for inserting the images for me and explaining how to do it.

I noted in my previous post that the z2=0.9 curve has a “tail” that the z2=0.5 curve doesn’t. But, other than that tail, the shape/slope of the curve doesn’t change at all as z2 changes.

I’d be interested in your thoughts on the following quirks(?) of GRT.

I found by trial and error that the curve doesn’t start growing a tail until z2 > 0.800. For any value of z2 > z1 and < 0.800, the curve doesn’t change at all. Also, the tail does strange things when you play with z2. For instance, it’s there for z2=0.820, but disappears again for z2=0.821. Could be a kink in the code that needs to be worked out, or maybe immaterial?

Although the vivacity curve doesn’t change for z2 < 0.800, the pressure curve does change. As z2 is increased, it looks like the area under the pressure curve decreases, so less work is done to accelerate the bullet in the barrel. Although you get more muzzle pressure, the MV is slower. I’m thinking that’s because more of the available energy is being blown to the atmosphere instead of accelerating the bullet in the barrel.

At z2>0.9, the transition point is so far out on the curve that the bullet has already exited the barrel. So, while you can enter values for z2>0.90, it has no effect on the other parameters.

I sure would like to know the z2 value for W231. So far, I haven’t been able to tweak GRT to agree with my chonograph like I have done with QL.
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Old June 12, 2019, 11:42 PM   #47
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Quote:
Originally Posted by higgite
I sure would like to know the z2 value for W231. So far, I haven’t been able to tweak GRT to agree with my chonograph like I have done with QL.
I would, too, since 231 is the only handgun powder I've ever used. (Trail Boss has been procured for .44 Colt, but not chronographed as yet.)

I haven't had time to try GRT with the value of z2=0. that Unclenick suggested.
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Old June 13, 2019, 08:51 AM   #48
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Quote:
I haven't had time to try GRT with the value of z2=0. that Unclenick suggested.
I tried that, but the software won't accept z2 less than z1. For instance, z2=0.8345 for N320 in the GRT database. If you enter a value for z2 that is greater than z1, it will accept it. But, if you enter a value for z2 that is less than z1, z2 automatically reverts to 0.8345.
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Old June 13, 2019, 01:55 PM   #49
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I suggested 0.9. To get there, I took the vivacity values listed in QuickLOAD and plotted them in Excel for the values after Z1 and used the polynomial trendline fit to spot the second inflection better than I had in my guess of 0.73. That turned out to be my eye fooling me.
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Old June 13, 2019, 03:30 PM   #50
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All,

I'am sorry I haven't discovered this discussion going on for so long. I'm in fact connected to the GRT development team and apologies for my late response:

1. Powders: We wrote to Winchester, Hodgdon/IMR, Ramshot, Alliant and Western, to ask them for their powders caliometric test results. Those are needed to add a powder to GRT. I consider this "early work in progress". You might speed up their attention, by asking them to provide data to the community.

2. Read the manual: GRT can be run in your favourite mode in metric or imperial units exclusively or any other imaginable mixture of it. You can configure each field according to your likes

3. SAAMI: Currently, GRT only refers to calibers (over 900) described through CIP (the european standardization body). We have found four or five errors in measurements and also one methodological error and reported them already. We are currently preparing SAAMI calibers to be added to the DB. Honestly - it's a pure mess... but we'll keep on trying

4. Quickload-Data: about anything saved in QL can be imported to GRT. Read the manual / click on "File|import" or use your right mouse button. (this includes powder data)

Have fun
Barney

Last edited by BEG; June 13, 2019 at 03:49 PM.
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