QuickLOAD Experiences

R

RougeLeader

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In a previous thread the software package QuickLOAD was referenced in a discussion regarding the 38 Special, specifically a loading that I had posted. I'm not going to argue the danger of my loading and fully accept that it is a bit beyond pushing the limits of the 38 Special, but I am curious as to your experiences with the software. I acquired v3.8 immediately after that posting and have noticed quite a bit of variance between the software and loading manuals.

What have your experiences been with QuickLOAD? Have the pressures and velocities been close to reality, is there a factor of safety built into the package beyond the absolute pressure value, etc. Just curious as to what you all think of the software and how you use it in your load development.

I will state here that I am a noobie to this software, having only used it for ~2 weeks. I'll also state that I do know better than assuming any package, QuickLOAD, FLUENT, or my own OpenFOAM runs, completely reflect reality.
 
There are several limitations to the software that you have to learn to live with or work around. First, realize that, depending on brand, the canister grade powders we buy are held to either ±3% or ±5% of burn rate. QuickLOAD's author's main hat trick is that he developed a method (built into QuickLOAD) that can deduce powder properties from data taken from a vivacity bomb. Most powder companies don't publish complete specifications for their powders, keeping some of it proprietary, so the author had to figure out a way to measure what they weren't publishing. A limitation of this is the author must purchase powder to test in the bomb, with no idea whether he got a lot that was average or on the high or the low side of tolerance. This affects the prediction accuracy.

There are also some arguments you can't make. QL doesn't have a throat position in its virtual chamber, so you don't see the effects of bullet proximity to that. It doesn't have real primer data, as primer manufacturers change that more often than the public realizes and don't usually announce it. You can manipulate the start pressure to compensate for some of this, but only with feedback about actual performance.

Another factor is that QuickLOAD generally assumes a perfect minimum chamber and minimum cartridge case capacity to create predictions that default on the high side, for safety reasons.

The best thing, when you can do it, is to find data for your load that has pressure and velocity published, as it is at Hodgdon's site. Then you can tweak QuickLOAD to get a closer match to their data. Being a powder company, they have reference powder lots that have properties representative of what they order and do their pressure testing with that. So you get a better idea from those measured results how the QuickLOAD model compares. After tweaking, you can change bullets and powder charge and expect you are closer to correct for the average lot of powder of your chosen type.

Read the 6 mm BR site's article on using QuickLOAD. Read Chris Long's paper on tweaking QuickLOAD to match what you are measuring. You can usually make it come pretty darn close to what is actually happening. It then becomes an invaluable tool for telling you what to expect from making changes in a load.
 
I've been measuring volume of fired cases( weight of water in grains to top of neck).
It does change volume inputs some.
The biggest volume change seems to be with wildcats. 7mm-08AI for example.
I do tweak max pressure for 250 Savage, 284 Win. But otherwise when looking at loads i keep them 4000 under max pressure, for my max pressure ceiling.

As QuickLoad will even tell you, they are not meant to be used in place of a published load manual.
 
I have been a user of quickload for a very long time and Unclenick is spot on as usual, and the articles he published are great reading. One thing I will say is that quickload does a lot better with bottle neck cartridges over straight walled cartridges.
 
Uncleinick: Thank you for a well written straight forward explanation .

I would have thought it impossible to overcome all the variables with a program like that.

Kudso to the guy, its amazing work and its nice to see you detail it out as to how it gets that way.
 
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