Wildcat load development
 

Looking for some opinions on load development for my new build. I just got my new rifle and custom dies for a rifle I'm going to try. It's a one off cal so there is no load for it in any of the data sites or books. It's basically a .375 Ruger case necked down to .358 which is very close to a .358 norma mag just a hair bigger. I'd like to try H1000 powder and 225 accubonds. The next closest that I Could find is .358 STA but that's a bigger case although they do have data for H1000. What I've been reading for the last while is to fill the case to the bottom of the neck and weigh the powder. Then try 70% of that number and try it. I did that and the case to the bottom of the neck holds 88.1grs. Multiplied that by .3 and subtracted from 88.1 and that gives me 61.6grs. The data for the 358 norma is comparable to the min loads and that case is a hair smaller in all dimensions. The brass will need to fire form a bit in the shoulders so I'll have to get the real results on the Chrony after the second load but just wondering what guys that know think of starting with that load.

If it is just a "hair bigger" than the 358 Norma I would start there, but I can get into my quickload program and check, there is likely a cartridge already built on it.:)
Cat

If there truly is no load data anywhere then for sure I would run it through Quickload, with accurate case data including H2O volume before I tried shooting any loads.

Discussion of this Wildcat has been ongoing since 2007 and reamers started coming out in early 2008, so I find it hard to believe there are reamers and dies but no load data of any kind. Did you try talking to the Reamer maker to see if they know of anyone who is an expert in chambering and setting up this round?

I’m picking up references to this wildcat being very similar to the .35 Newton cartridge.

Use 375ruger data with 235gr bullets and drop down 10% in powder charge from min . You will be in the safe . I shoot a 358STA and I used 340wby data but started 10% under min

Reamers and dies available I am pretty sure it would be on Quickload :)
Case length and water capacity please .......
Cat