While surfing the web, I ran across several posts on making .351 WSL brass from .223 Remington cases. I decided to do some experimentation, and while not perfect (the rim is 0.032" smaller than factory brass), the modified cases functioned well in my 110 year old Model '07. The process isn't much different than making .300 Blackout from .223s. Besides, I have much more .223 brass than I do .357 Max and no lathe to turn it on.

At the range today I found 2 or 3, 351 brass , I think it`s the first time I have ever seen any!