How do wildcatters come up with load data?

[Dan877]

If someone is creating a new wildcat how do they come up with load data? Is there a ballistic table or calculator or software in which you put in the dimensions of the case and bullet and the powder type and it suggests a safe starting load? Or is it a matter of finding the closest "well documented" cartridge and basing your start loads on it? Or is it just a matter of know-how and experience? I'm not trying to create a new wildcat, and probably never will, I'm just curious and trying to learn more about the process.

 

[1000yardstare]

Some of us with receding hairlines still have our old Powley Computer from the 1960s. This cardboard slide rule uses the case capacity of water in grains to calculate a starting load of an IMR powder of suitable burning rate using expansion ratio.

The Powley was based solely on IMR powders so there are gaps in burning rate especially above 4831. A lot of the powders we take for granted now didn`t exist back then.

There are more sophisticated computer programs available now. But I don`t own a smart phone and have never played a computer game. So I will stick with my Powley.

 

[Erik Cortina]

I use QuickLOAD.

 

[bheadboy]

I take the basic case, compare water capacity of original and wildcat version, then adjustin for increase or decrease take the medium load for the original case - modified by the water volume increase or decrease and start there, doing a ladder up as long as pressure remains reasonable.

Bob

 

[serial # 001]

Dan877, I have looked in a loading manuals and found the nearest smaller case of the same caliber. Then I use the maximum load for a starting load. Years ago I used to make duplex loads to wring a little more velocity from the case. Now we have so many powders that is not necessary. Maximum velocity for a given bullet is generally why I made wildcats. One time I did one just to have a short action that would duplicate a magnum's performance. This give lots of room to back off to find the absolute best accuracy.

Now we can buy those in factory rifles.

 

[Shummy]

After building a wildcat I wanted to try in Excel, comparing several known cartridges to make sure my calculations were correct and came up with what I wanted for a print/water capacity, I started looking for some way to come up with some starting loads........and I found this:

http://loadammo.com/

You can build the cartridge/wildcat of choice with the demo, and calculate grains capacity based upon user input,which was very close to what I had calculated in a bit more time consuming way.

The load data/powder suggestion in the demo is only available for 30 cal bullets up to 150gr I think. Pay the $65 and you get all the weights and calibers.

Anyway I bought it and it is accurate in estimating speeds and pressure for loads I have existing in other rifles. Still a couple weeks out to see how the wildcat does.

I didn't do the Quik load because I it looked like there are two packages needed, one to design a cartridge and then another to calculate the load data? Am I correct on this?


Thanks,
Shummy

 

[Erik Cortina]

QuickLOAD alone can do that. All you do is take the parent cartridge and increase/decrease H2O capacity and it will give you a list of powders that would work with that case using any bullet you select. It works really good and it's easy to use.

 

[moosetracker]

QuickLOAD alone can do that. All you do is take the parent cartridge and increase/decrease H2O capacity and it will give you a list of powders that would work with that case using any bullet you select. It works really good and it's easy to use.

+1 for Quickload, that's what I use as well.

 

[TonyR]

QuickDesign can also be used to get the cartridge case data. It is a companion program to QuickLoad that allows you to design your own wildcats either by modifying parent cases or from scratch including dimensional drawings. The resulting cartridge data can be imported by QuickLoad for load development.

 

[bheadboy]

Erick, it seems quickload does automaticly what i do and described above, however i have been get there without the cost of another program, and for years before quick load existed.
comparing water volume to original case works.
Bob