the 700's in 17 fireball,221 fireball and 300 aac blackout all use a different bolt than the 223.
That is incorrect - the .17 Fireball, .221 Fireball, and .221 Fireball-based .300 AAC Blackout all use the same 0.378" boltface as the .223 Remington.
Snowwolfe,
A CZ, Rem. 700, Savage 10 or 11, or Ruger American are all decent platforms. The Savage is economical and has the Accu-Trigger. Ruger Americans are also economical but I don't have any personal experience with them.
I've shot a buddy's CZ and it just screams quality but costs twice as much as the other rifles mentioned.
If you're open to the idea, the Savage Custom Shop could assemble a LH walking varminter in .17 Hornet (25gr. bullet
3515fps).
George