Doubtful it will be much quieter, but in general any reduction in velocity and gas volume should make it marginally quieter. You're going from 23-27grs of powder pushing a bullet at 3000fps down to 2100 fps pushed by 10-15grs of powder.
I hunted with a 125gr load last year, but may try cast subsonic suppressed this year (short range from a stand). Suppressed .300 is ridiculously quiet.
