yes a .223 is a good choice that is if your buying your ammo . some thing i discovered some time ago was that a rimmed case cartage is way easer to handle ,mostly to extract ,than a rimless ,unfortunately there are not alot of such cartridges available . and the encore tho accurate is not the most and easiest gun to reload it a hurry so every little bit helps.
for a bigger caliber the 300 mag works very well . but check the head space ,some of them are deaper than they need to be.