At SAAMI spec pressures, 10mm eats .357. A max 10mm Auto load will put 180gr bullet out at 1250fps from a 5" barrel. A max .357 load will put a 180gr bullet out at 1150fps from a 8" barrel. 10mm/155gr goes 1450fps, .357/158gr goes 1250fps. If the specialty manufacturers are getting significantly more than that they are exceeding industry standard pressures.