[ziondio]

I am looking for a little help with some starting loads for a cartridge that I built.
it is simply a 300 wsm necked up to 45 auto. I have been using 300 grain .451 sierra projectiles and a full case of h100 and am ready to work up some loads with some faster more appropriate powders. Any help will be appreciated.

 

[rawright54]

Wow! As I read it, this new cartridge has a length of about 1.3", compared to 0.65" for a .45 Auto. That makes a huge difference in the space available for powder, and leaves a lot of room for errors that could be harmful. Worse, I can't find any reference to a bullet of that weight for the .45 Auto. The .450 Marlin comes kinda close, but it's a straight walled case. Without proper gear to measure C.U.P. I'd be really cautious about loading that beast.

I'd try Reloader 7 at about 45 grains ( Speer mentions, for the .450 Marlin, a minimum of 52 grains for a 300 gr bullet), but the 450 has a case .40" longer. You might even want to err on the side of caution, and drop that to 40 grains, just to be safe. But have a 3/8" dowel handy to push the bullet out, if it turns out to be too wimpy a charge to clear the muzzle.

 

[Bindernut]

A lot more information is needed on your new creation before anyone can help you with your project. Case volume, intended velocity/energy range, etc

Personally, if I was working on a wildcat these days I would probably invest in a copy of QuickLoad.
It allows you to enter data for a wildcat case besides the cartridges already in the software's library. Once the case/bullet data is entered, it'll calculate a range of load data using a whole range of powders.
http://www.neconos.com/details3.htm
Keep in mind that the data is just calculated and the final end result is up to you to test...but it is a lot better than random guesswork and still needing to test.