My rifle came back from the Smith, and it has the feel and look of a real hunting tool. Now it's time to start load development. So, I'm asking for advice from some of you who have experience with wildcats.

Actually, this may be an easy one, because there is some published loads for the 358 Norma, and the 9.3x64. I started with IMR 4895, using published loads for 250gr bullets in the 358 Norma. With I4895 I was able, so far, to go 3 grs over the max load shown for the 358, with no signs at all of excess pressure. I started 5 grs under max for the 358, using two reference sources. I don't plan to go more until I have a cronograph, and can actually test for accuracy. My goal was just to shoot it some, and to find some starting loads.

But today I made a hopefully significant discovery. The water capacity of 9.3x64 RWS brass is 84.4 grs, and for 338 brass necked up to 9.3 it's 83.9 grs. So, essentially my wildcat is darn near the same as the 9.3x64, but with a belt.

So, my question is do you think load data for the 9.3x64 tells me anything useful for developing loads for my wildcat? Naturally I would like to use some 286 gr bullets, and powder other than I4895, so a starting place referencing 358 Norma generally ends with 250 gr bullets. RL 15 is promising, and I have data for the 9.3x64 for that powder, and several others.

Anyway, your feedback would be appreciated.

KB

Sounds like a reasonable place to start if you start with the light listed loads. The 9.3x64 is by natuer a fairly hot loaded cartridge from the factory.
Sounds like a pritty neat round for AK. I envy you being there right now I won't be home for another 31 days.
Keep us posted on how it works out for you.