Calibrating (“Truing”) QuickLOAD

[kelbro]

Interesting article. My latest sample was a 185 Jug in a 24" 308 about .015 off touching the lands. Adjusting the Varget Ba to 0.66 (very close to Jim's number) made all of my velocities line up without adjusting any more parameters.

 

[Webster]

I’ve documented my methodology to calibrate (“true”) QuickLOAD that gives me predicted velocities that are typically within +/- 5 fps of my measured velocities.

The foundation of this method is, for a given handload (caliber, powder & charge, and bullet), to enter the obvious factors (i.e., actual bullet weight and diameter, cartridge and case length, barrel length, and maximum case capacity) and an improved estimate of the weighing factor. Then adjust the:

• Powder Burn Factor until the predicted and measured velocities match for large jump handloads, then
• Shot Start (Initiation) Pressure until the predicted and measured velocities match at different jumps.

I’ve tested this on three rifles (.222 Remington, .22-250 Remington, and .308 Winchester) using two different bullets (52 gr Berger Flat Based Varmint and 168 gr Sierra MatchKing) and two different powders (IMR4198 and two different lots of Varget). Adjustments I needed to make to the Burn Rate Factor and Shot Start (Initiation) Pressure to calibrate (“true”) QuickLOAD were within accepted ranges.

If this interests you, my methodology and results are described in more detail in the attached pdf document.

I’d welcome your thoughts, comments, and suggestions on what bullets and powders to apply this to next.

Your arbitrarily changing two parameters to force the program to give the results you want???

 

[222Jim]

Your arbitrarily changing two parameters to force the program to give the results you want???

It's not arbitrary. Both parameters are open to tuning by design in the QL program.....burn rate because powders vary lot-to-lot, and shot start initiation pressure because differences in throats/leade/bullets/jumps will results in different pressures. What I developed is a structured approach to adjust these two parameters that works for me and, based on feedback from others, usually works for them too.

 

[222Jim]

Interesting article. My latest sample was a 185 Jug in a 24" 308 about .015 off touching the lands. Adjusting the Varget Ba to 0.66 (very close to Jim's number) made all of my velocities line up without adjusting any more parameters.

Nice to received feedback it works for others. IT's not perfect; one person I was corresponding with just couldn't get things tuned. But most feedback I've received has been positive. Thanks again.

 

[PhilC]

I've done the same with H335 and IMR4198. My powder jugs are marked with the Ba number I used to match actual chrono data and temperature. Good enough for my needs.

 

[222Jim]

I've done the same with H335 and IMR4198. My powder jugs are marked with the Ba number I used to match actual chrono data and temperature. Good enough for my needs.

Did you know that QL also allows you to create your own powder files? I copied their file, changed the name of it from "qloadfw" to "qloadfw - Adjusted" and then input my own Ba values. I then name the powders according to the caliber and bullet they were determined for.

A side benefit of this is I could also erase the hundreds of powders I'll never use. I keep the original file "just in case", but it does make my life using QL a little simpler.

 

[Pirate69]

Did you know that QL also allows you to create your own powder files? I copied their file, changed the name of it from "qloadfw" to "qloadfw - Adjusted" and then input my own Ba values. I then name the powders according to the caliber and bullet they were determined for.

A side benefit of this is I could also erase the hundreds of powders I'll never use. I keep the original file "just in case", but it does make my life using QL a little simpler.

View attachment 1708275

I took a look at the qloadfw file but was not able to open it. Could not figure out which format to use to open it. Maybe I will find the answer later but another question.

Let's say I model a cartridge load using the QL qloadfw data (as provided by QL). I compare the actual velocity results to the QL results and adjust the Ba data to match the actual velocity. I now save the file with the manually adjusted Ba value. I am thinking that the saving of the file does not affect the original qlfw file; it only creates a saved input have contains a modified Ba factor. I do not what to do anything that will modify the original qloadfw file. Is my thinking correct?

Thanks in advance,
Pirate69

 

[222Jim]

I believe so.

To open, edit, etc. the QL powder file, use Notepad which is an option in Microsoft (if you're on Apple, I've got no idea). I opened the file, then saved a copy in the same location with a different name. Then when I open the powder "folder" in QL I have two files to select from.