With some exceptions (like say 77gr being close to M80), 5.56 55gr and 62gr is kinda close.
BDC's are meant for fighting. Not ultra long range precision
On the TA-31, that reticle was designed to put a 62gr M855 projectile on a 5’10” tall, 18” wide target out to 800yds in either a 14.5” barrel or 20” barrel, depending on NSN suffix.
There was a reason the guys shooting SMK were issued a different optic.