I'm at a loss on the methord used to develop starting loads for new widcats! Ie when one has formed a new case how do you decide (a) what proj weight& (b) what powder (as in burning rate)& what charge to start with thanks

First, you decide which projectiles you want to use based upon the application you have in mind. For example, you might choose a 160-grain round-nose for a 6.5mm magnum wildcat for shooting elephant, but not prairie dogs. Bullet choice is basically just common sense!

Then you must determine the case volume in grains of water by filling some cases with H2O and weighing them before & after filling. Powder type and amount choice is based on this and the sectional density of the bullet you chose. Next you use some tool like one of the computerized loading programs or the Powley Computer (available free on-line) to determine a starting load for a cartridge of that caliber and case volume.

After you have chosen and tested that safe staring load, work from there is your responsibility.