Any experience using the Hot Core Speer 275 grain 338 cal bullet or the 338 cal 250 grain Grand Slam bullet on big game? Black bear, caribou, elk

Couple of friends and my son have used the 275 on deer and elk with very good results in 338s, no expereince with the 250s. have used the 285 375 GSs with good results though. Also, the 275 gr Speer 338s were Elmer Keith's favorite 338 bullet.