150 vs 125 ?
i am going to assume you are using a .30 cal .....308 or 30.06 as 150 grn is the most common load . This being said . Using big game bullets such as the nosler partition or new barnes tsx , etc going from 150 to 125 would be great ...less recoil ,more speed ,flatter tracjectory at longer ranges provided your specific gun liked a particular load. Most .30 cal's love bullets in the 150 -168 grain . A 125 grain in 30.06 performance should mimic a .270 with the 130 grn . Im of the opinion that the time ,cost ,working up a new load etc is only productive if your getting recoil sensitive or training a newer ,younger shooter .There are also factory managed recoil loads .