Yeah, but first, will that heavy 200gr hardcast in 10mm feed reliably?
Color me skeptical.
Second, Buffalo Bore has some 357 fodder with more energy on tap, matching that 10mm load.
Third, if the 200gr slug DOES feed reliably, it can't have all that fat a flat-nose on it. So it may be strong on power but not as strong in terms of wound ballistics. I'd like to see a pic of the stuff. I assume this is Doubletap, right? Lessee...
Huh. OK, it DOES have a good nose profile. Cool. Great stuff for a 10mm revolver.
But does it go up feed ramps OK?