Re: 223 (8" twist) or 22-250 (14" twist)
The 243 with a 9 1/8" twist or 10 twist is excellent for varmints of all descriptions and certainly enough for most deer...
I like to take BOTH a 223 and a 243 when varminting and use the 223 for the close shots and the 243 for the longer shots. You'll need to cool the barrel of the 243 a lot more than the 223 barrel or you'll cook it pretty quickly.
If it's long it can't be wrong... LDHunter (Long Distance Hunter) from the Piney Woods of NW Florida. I hunt clearcuts for scrawny whitetails... ;)