I have used the 125 grains out to 190 yards on deer, performed flawlessly every time it entered the vitals. Quite honestly I don't remember how many deer taken with the whisper, maybe 11 or 12, none ran over 70 yards, some piled up and didn't run. I believe you already made your mind up, but I'd just like to say to stay away from 150 gr sp ammo. I tried remington bulk 150 gr loaded up. Just not enough steam to mushroom the bullet. I had a heck of a tracking job on one account, on the other I got lucky enough to finish the animal quickly with a second shot. Those corbons will do fine, I loaded some in a herret a few years back. Another option may be the single shot pistol bullet (I believe from speer,,,,, maybe sierra). I can't recall if I was using it in a tcu caliber or in the whisper, at any rate if they make it in a 30 no matter the grain, give it a try. It has a thin jacket and will do well at low velocities. One other option is the hornady v-max it will do a very fine job. I played around with a load in 7 tcu and 7-30 waters, both worked great on deer down to low velocities. No large holes as associated with varmint bullets at high velocities.