I don't load FMJ in .357, but all my 158s regardless of manufacture(JSPs, JHPs, XTPs and GDs) started with the same load recipes, and when finally tweaked to shoot well outta my 686, ended up pretty much to within half a grain of each other with the same powder.
In other words, as long as you start at or near the suggested starting load with a similar weight FMJ bullet, you should be safe.