Consensus among many FT/HFT shooters (if there is such a thing ) seems to be that they don't group well beyond 35-40 yds in most 12 ft.lbsf rifles. The speculation is that it's to do with rifling twist rates. Launched at the lower spin speeds of 12 ft.lbsf, pellets start to rely on drag stabilisation at longer ranges so diabolos win out, whereas the bullet shaped pellets start to wobble. Grouping and wind performance then go out of the window.

With FAC they spin faster so they stay stable for much longer.

As I say this is speculation but seems to fit most accounts I've read. FAC: yes, sub 12ft.lbsf fine up to 35 yds or so.