Fiocchi 357 Magnum 142 Grain Full-Metal-Jacket Truncated-Cone (FMJTC)
👍 Low cost locally, cycles the action on a Coonan 357, with full-power recoil spring, and small-radius firing pin stop. (Update: not 100% actually.)
I measured 5 shots at 1216fps, with a high extreme spread of 115fps, out of a 5″ Coonan 357.
I expected my numbers would be closer to their numbers, so I should measure again.
I pulled one round: the bullet was 142.7grains with an exposed lead base, there were 8.3 grains of powder.