In the QL program there is a so-called "weighting factor" that has to do with percentage of unburned powder.

This is a critical factor in the QL results that are rendered, and how it's applied does not seem consistent from cartridge to cartridge and consistent with their "reasonable default" values for typical bottle neck and overbore cartridges, etc.

Does anyone know much about this "weighting factor?"

Regards, AIU

quote:

"weighting factor

The weighting factor has to do with the shape of the case. I stole this from a QL review on 6mmBP.com.

The Mysterious Weighting Factor--QuickLOAD has a "weighting factor" it uses to help tailor output values to cartridges of various different shapes and sizes. The default for bottleneck cases is 0.5. "Overbore cases" have been assigned a value of 0.33. But if you click on the 6mm Dasher cartridge profile, the weighting factor is 0.4. Presumably that represents some kind of judgment call, but QuickLOAD doesn't really provide any criteria for assigning a weighting factor to a particular cartridge that is not a "typical bottleneck." For what it's worth, the default value for the 6BR is 0.5, but we got better results using a value of 0.45.

For the full review http://www.6mmbr.com/Quickload.html

My concern is that this "weighting factor" is set too high for the 338 Rem Ultr Mag. - that is, .065. Seems like it should be set closer to 0.33 for "over bore" cartridges. Any thoughts? Regards, AIU

quote:

Originally posted by Ackley Improved User:
My concern is that this "weighting factor" is set too high for the 338 Rem Ultr Mag. - that is, .065. Seems like it should be set closer to 0.33 for "over bore" cartridges. Any thoughts? Regards, AIU

I would think the same as you AIU. Ramrod is right, “QuickLOAD doesn't really provide any criteria for assigning a weighting factor to a particular cartridge that is not a "typical bottleneck” or at least it seems that way. The weighting Factor represents friction of unburned powder and produced propellant gases that move forward with the bullet.

“Reasonable default values range from .75 (cylindrical cases) to .33 (overbore bottleneck cases)”. OK?

Weighting Factors

45/70, .75 (just throw this one out because QL couldn’t find it’s ass with both hands and a flashlight when it comes to straight cases)

300 RUM, .7
338 RUM, .65
30/378 Wby, .52
300 Wby, .5
340 Wby, .5
25-06, .55
257 Roberts, .5
220 Swift, .4

I have no idea what all this means but I find it interesting.

If there were ever "over-bore bottle-neck cartridges" it would be the 30/378 Wby or the 300 RUM, even the 338 RUM. Shouldn't their "weighting factors" be closer to 0.33? I don't get it. Regards, AIU