I am wondering what your rate of twist is in your 223, I can not get the 60 grain partitions to shoot better than two inches at best from my rem 700 with a VSSF barrel that shoots 1/2 " and better with 50 grain ballistic tips. It has a 1 in 14 twist. oops, I forgot to mention it is a 220 swift so speed is not the problem
I couldn't get them to shoot either until I tried them with IMR4895.
My load looks alot like LBP's.