RE: .243 or .270 which is best for deer
As stated there is no reason to move from an 06 to a 270. They are basically the same.
I"ve had good luck with the 243 and proper bullets. Yet at home I can pick and choose shots and pass up shots. I"d always lean to more horsepower, especially in a trophy hunting situation. I can't see going wrong with what you have. Yet for whitetails I often hunt with a 300 mag and if I shoot a deer end to end, the bullet still won't always allow total penetration.
Kinda a take your pick situation here. Depends on exactly why you want a new round. FWIW I always feel that a 270 kicks worse than any 06 that I"ve shot too.
Jeff