Jack Monteith
11-30-2006, 02:23 PM
There are two ways to develop a load for cartridges that don't have available reloading data. These aren't a substitute for the data for common cartridges in the current reloading manuals. The first method uses the Powley Computer. This was a complex but useable cardboard slide rule using the math of Mr. Homer Powley. Several computer programs using his math are now available.
Suggest-A-Load, free, DOS
http://www.john-ross.net/suggestload.htm
WinLoad, free, Windows
http://www.stickledown.co.uk/
Load From A Disk, $, Windows, more features
http://www.loadammo.com/
The original Powley Computer:
http://geocities.com/nelstomlinson/sliderules.html
The Powley Math:
As the author has taken this page down, and it's only available on Wayback, I'd advise anyone interested to save it to disk now.
http://web.archive.org/web/20041126010343/http://www.aeroballisticsonline.com/ballistics/imrpowder.html
The second method uses the QuickLoad program, which apparently uses a different and more sophisticated mathematical model.
By UncleNick:
Here is a direct link to the QuickLOAD page at NECO:
http://www.neconos.com/details3.htm
QuickLOAD was developed by a fellow engineer, and you can tell when you get into it. Unlike many other calculators, it makes no generalized assumptions about the characteristics common to powders. Instead, it uses data from laboratory testing of actual powder samples. This data is not published by the powder makers, who consider it proprietary (at least, it is until someone measures it).
A couple of interesting things pop out of this approach. Not every powder you might buy is on the list because they haven't all been tested yet (though the vast majority have been). Secondly, you will find a few disagreements between the positions of some powders on published burning rate charts and the burning rate order in the QL list. This is due to lot variation and may mean the particular lot tested for QL was not quite typical. The published lists may also be wrong, since even the powder makers don't want to foot the $50K bill for complete batteries of tests on each of their powder lots. As a result, QL makes no guarantees for their calculated results. You still need to back off predicted maximum loads and work them up.
Other kinds of detail you don't typically find elsewhere include that QL gives you the opportunity to enter the actual configuration and dimensions of your bore (how many lands and grooves and how deep and wide they are) to improve the accuracy of its muzzle velocity predictions. It has a case water capacity estimator so you can measure your fire-formed cases and replace the standard case capacity value with the estimate for more accurate pressure and powder burning predictions for your gun. It has features for everything from generating lists of powders and loads that meet a particular pressure or muzzle velocity, to full recoil effect estimation. There are 13 different result numbers generated for the recoil effects, alone. If you want the weight of the scope included and want to know how many peak pounds of force that scope will be subjected to by a particular load, here it is.
The program comes with an integral companion exterior ballistics program called QuickTARGET. It imports a QuickLOAD result directly to generate exterior ballistic tables and charts, though you can put any bullet or muzzle velocity in manually. It also plots shots on targets and you can see effects of sight adjustments and wind, etcetera.
One feature of QuickLOAD, for those interested, is it predicts bullet barrel time for a bullet in milliseconds (ms) based on the powder and bullet combination. This result and its number are used with Chris Long's Optimum Barrel Time calculator to predict sweet spot loads. Long uses QuickLOAD to get predicted matches to traveling pressure wave phase in the barrel. Since two powders can produce the same muzzle velocity with different barrel times, based on the burning characteristics, the QuickLOAD type calculation is needed for accuracy of this number.
Faults:
Like most high feature programs, most QuickLOAD users will never bother to try, much less actually use all the features or data. Too bad. It is an education just to run around and see the purposes of all these things. The large bullet database seems to have been entered hastily or acquired from unreliable sources in spots, and so it is off a bit or incomplete in some cases. For bullets you work with a lot, you want to measure them for yourself so you can enter any corrections to the date that comes with the program. You enter your own bullets by editing an existing bullet, but saving the changes under a new name in order to leave the original bullet's data intact.
There is a warning at the start of the program that its results are less precise with straight wall cases than with bottleneck cases, but that it errs on the side of exaggerating pressure in straight cases, so it errs on the side of safety. Relative results are always very good, so matching pressure to a known load works well. You can compensate for the straight wall error by adding a few % to the case water capacity.
Suggest-A-Load, free, DOS
http://www.john-ross.net/suggestload.htm
WinLoad, free, Windows
http://www.stickledown.co.uk/
Load From A Disk, $, Windows, more features
http://www.loadammo.com/
The original Powley Computer:
http://geocities.com/nelstomlinson/sliderules.html
The Powley Math:
As the author has taken this page down, and it's only available on Wayback, I'd advise anyone interested to save it to disk now.
http://web.archive.org/web/20041126010343/http://www.aeroballisticsonline.com/ballistics/imrpowder.html
The second method uses the QuickLoad program, which apparently uses a different and more sophisticated mathematical model.
By UncleNick:
Here is a direct link to the QuickLOAD page at NECO:
http://www.neconos.com/details3.htm
QuickLOAD was developed by a fellow engineer, and you can tell when you get into it. Unlike many other calculators, it makes no generalized assumptions about the characteristics common to powders. Instead, it uses data from laboratory testing of actual powder samples. This data is not published by the powder makers, who consider it proprietary (at least, it is until someone measures it).
A couple of interesting things pop out of this approach. Not every powder you might buy is on the list because they haven't all been tested yet (though the vast majority have been). Secondly, you will find a few disagreements between the positions of some powders on published burning rate charts and the burning rate order in the QL list. This is due to lot variation and may mean the particular lot tested for QL was not quite typical. The published lists may also be wrong, since even the powder makers don't want to foot the $50K bill for complete batteries of tests on each of their powder lots. As a result, QL makes no guarantees for their calculated results. You still need to back off predicted maximum loads and work them up.
Other kinds of detail you don't typically find elsewhere include that QL gives you the opportunity to enter the actual configuration and dimensions of your bore (how many lands and grooves and how deep and wide they are) to improve the accuracy of its muzzle velocity predictions. It has a case water capacity estimator so you can measure your fire-formed cases and replace the standard case capacity value with the estimate for more accurate pressure and powder burning predictions for your gun. It has features for everything from generating lists of powders and loads that meet a particular pressure or muzzle velocity, to full recoil effect estimation. There are 13 different result numbers generated for the recoil effects, alone. If you want the weight of the scope included and want to know how many peak pounds of force that scope will be subjected to by a particular load, here it is.
The program comes with an integral companion exterior ballistics program called QuickTARGET. It imports a QuickLOAD result directly to generate exterior ballistic tables and charts, though you can put any bullet or muzzle velocity in manually. It also plots shots on targets and you can see effects of sight adjustments and wind, etcetera.
One feature of QuickLOAD, for those interested, is it predicts bullet barrel time for a bullet in milliseconds (ms) based on the powder and bullet combination. This result and its number are used with Chris Long's Optimum Barrel Time calculator to predict sweet spot loads. Long uses QuickLOAD to get predicted matches to traveling pressure wave phase in the barrel. Since two powders can produce the same muzzle velocity with different barrel times, based on the burning characteristics, the QuickLOAD type calculation is needed for accuracy of this number.
Faults:
Like most high feature programs, most QuickLOAD users will never bother to try, much less actually use all the features or data. Too bad. It is an education just to run around and see the purposes of all these things. The large bullet database seems to have been entered hastily or acquired from unreliable sources in spots, and so it is off a bit or incomplete in some cases. For bullets you work with a lot, you want to measure them for yourself so you can enter any corrections to the date that comes with the program. You enter your own bullets by editing an existing bullet, but saving the changes under a new name in order to leave the original bullet's data intact.
There is a warning at the start of the program that its results are less precise with straight wall cases than with bottleneck cases, but that it errs on the side of exaggerating pressure in straight cases, so it errs on the side of safety. Relative results are always very good, so matching pressure to a known load works well. You can compensate for the straight wall error by adding a few % to the case water capacity.