I don't know if it is the "best" or not, but the 69 sierra is pretty decent and stabilizes in my Kimber Montana 223. That and the 63 SMP are about the only bullets from sierra that I will touch.
The Hornaday 75 BTHP may also stabilize (won't in my Kimber even after all the tweaking), and that'd be a good one to try too.
My LTR LOVES the 75gr Hornady mentioned above. The 69gr matchking, not so much. I'm using the data from Hornady's Service rifle section of their manual - BLC-2 in Lapua brass with Gold Medal primers. My load averages about 40fps slower than theirs, but the SD is in the single digits.
Kaiser Norton
