I also just picked up some .308 168 gr TTSX's for my Sako 300 WSM
. The Barnes machine for making them had been down for a while and they're catching up on back orders. I called the Barne tech rep a while back and he gave me an estimated BC of about .450
Having said that, just the other day, I found out that the Nosler E-Tip have just come out which is a similarly constructed bullet. They are made of the same copper alloy that Nosler uses to jacket their other bullets and gives less fouling than the all copper Barnes bullets. The only weights available now in the .308 are the 150 and 180 gr. The 180 gr has a BC of .523
Another difference is the E-Tip will expand down to 1800 fps and the TTSX down to 2000 fps. So right now I am leaning toward the E-Tip.
Here is a test done with the E-Ttip, PT and TTSX. The TTSX penetrates better, but the E-Tip expands a little more. A trade off.
24hourcampfire: Bullet Test Part II (Barnes & Nosler)