When starting with a "new" wildcat how do you determine a safe load to start? I know you guys don't just pour in the powder and top it off with a bullet and hope for the best. Is there a formula that helps find a starting load?
thanks

mostly it is based off case capacity for the bore size- and then you tie the rifle to a tire and hide behind a tree and pull the trigger with a string! Seriously after you know the case capacity you can calculate the loads or find a known cartridge of similar capacity, some of the different "programs" will help calculate- but there is a lot of trial and sometimes some error. You only live once so you might as well enjoy!

The best tool for figuring out the information you are looking for is QuickLoad. Cost 150 bucks, but you simply put in all the relevant cartridge measurements and Quickoad will give a list of powders, weights, and pressure. Of course this is all hypothetical data, but it gives a great baseline.

A lot depends on how closely the case capacity resembles a known cartridge for which starting load data is available. Otherwise, as the folks above have stated, you have to base your starting loads on the expansion ratio of the cartridge/bore combination, and use some sort of calculation device, be it a computer program or a gadget like the Powley Computer, a relatively inexpensive little cardboard slide rule that calculates starting loads based on case capacity, bore diameter, and bullet sectional density.

Thanks
I have my 20 tactical almost ready to go and the only loads I can find are for hodgon and vit. powders. I have always very good luck with IMR and wanted to give them a try in it.

Since this case is simply a 223 rem necked down could I start with a 40 gr. load for the 223 and work up or would this be unsafe? The only bullets available are 33 and 36 gr.

I am new to wildcatting so any info is greatly appreciated.