The .223/5.56 case has a lot of merit for something like this IMHO.
As a 6.5Grendel and 6.8SPC user, special cases and bolts get a bit old over time for use outside their specialized applications where they really excel over 'standard' offerings.
100's of yards isn't where I do much shooting and, sourcing ammunition right now is another issue. Sure, for feral hog plinking the 6.8SPC works well and the 6.5G would do the same at greater ranges very well.
However, the 6/.257 .223/5.56 variants are easy to form and relatively cheap. For a youngster or recoil shy or someone who doesn't need massive overkill, these "quarter bores" have a lot of attractiveness to me. Heck, I still look occasionally for a 257 Roberts!