the problem with the 300 rum (and possibly weatherby) is from what I have read, the lighter bullets seem to over stabilize. I have often thought about "how fast could I push a 125 gr Nosler" with my 300 rum, but most of the books recommend against it. I think stubblejumper on here shoots a fairly light bullet in his 300 rum (150 I think) to acceptable accuracys maybe he can offer more of a help. I dont think I will try the lighter bullets in my 300 rum since there are so many fine 180-200 gr bullets out there. When you are looking at bullets try to find one with a higher BC this may help.