Best 18-20” barrel S/A caliber?

I had a 18" 6.5 Creedmoor...2640-2660ish with 140-class bullets and 42.5gr H4350.

20" 6 Dasher...2800 with 105-107s and 32.4gr Varget.

20" 223...2800 with 80gr ELDs and 24.9gr Varget.

All will work great for paper or steel to 1000 yards.