Jim - I have a CZ 527 with 1 in 12 twist and a Savage with a 1 in 9 twist. I end up shooting 40-50 gr bullets in both of them, as I prefer the velocity over the bullet weight. Just me. I have a 22-250 that I shoot 50-55 gr bullets in. For the bulk of my prairie dog/ground squirrel shooting, I use 40 gr Ballistic Tips or V-Maxs. They are dramatic on small varmints as far as I can hit them - so far, about 300-350 yards. For further shots or windy days, I use the .22-250 or even my .243 (with 75 gr V-Max bullets.)
Rick