How do you decide on a starting load for your own wildcat design?

[briannmilewis]

I had better watch it, I may be wearing out my welcome asking too many questions here...but here goes again.

Say I make my own wildcat from a 30-06 case, and just cut the case down from 2.294" to 1.147", which will give me about 50% case capacity reduction.

To find a safe staring load, do I look at a moderate load in the 30-06 and use the same powder, a lighter bullet  to compensate for less powder, and finally halve the powder charge?

This forum has educated me enough to understand that it is probably not that simple.

This inquiring mind wants to know...

[Graybeard]

There really are several ways to go about it none of which are totally safe like using pressure tested loads from reputable sources but with wildcats you do what you must.

Best is probably determining the capacity of the case then determing what current round for which pressure tested load data exists is similar or same and use that data for your load development work. These days you generally can do that.

There is a program called Load from a Disk that is supposed to compute load data based on parameters you put into it but I've seen some printouts from it that were grossly unsafe so I personally have little trust in it as a predictor of safe loads. Still it is commonly used and liked by others.

Since I have no desires to develop wildcat cartridges it's not something I expect to ever face but if I did I'd go with the first route mentioned about and try to determine what exists now with the same or similar case capacity and use the data for it to develop loads for my new round.

[wackmaster]

I AGREE WITH GRAY BEARD!
I have developed a lot of wild cats. I start by comparing proven data from simmeler casses and then I always start with the slowest burning powder.
I wont to fill the case as much as possable. I always start with the lighest bullet I intend to shoot. You have got to get a base line to start with. bottem line is its a gess. if you are nervice about the first few shots strap it down to a bench and fire with a string.

[Catfish]

Well your new case is just under a .300 Savage so I would never build one but go with the .300 Savage for which I can by brass and dies at a reasonable price. I don`t mean that as a slam, but to point out to you that resurch you new round before you start to have your own built. Most wildcatters go with those that are already more or less standardedized. Those that don`t usually do all of their own work including cutting chambers and barreling. I have a barrel comming in .224 TTH ( .6mm case necked down to .22 cal ). The barrel will cost me $325 and I will mount it myself. It`s to replace the one just like it that I shot the throught out on so that is the only expence I`ll have this go round since I`ve already got the dies which cost around $ 100. If you really want to get into wildcatting watch for a used one that has die with it. Used wildcats are harder to sell than factory chambered guns and you can save alot of money on smith work.

[briannmilewis]

Graybeard, Wackmaster and Catfish: I was using the cut down 30-06 as an example, not going to build it. You are unanimous about looking for a similar case capacity and starting there cautiously. That's the kind of info I was looking for. It sounds obvious, but I am learning to assume nothing when it comes to this business of shooting and reloading. I am just grateful to have access to such sage advice.

[Nobade]

If you want to spend the bucks, buy QuickLoad and QuickDesign. You can design cartridges to your heart's content and see what they'll do before you buy any tooling. I use those programs all the time and really like the results.

[41 magnum]

Invest in P.O. Ackleys "Handbook for Shooters and reloaders"- Volumes 1 & 2.

There are hundreds of wildcats listed and just find the one closest in case size to yours and reduce 15-20%