Don't waste your time on the TMK Sierras. I shoot long range F class, so I order Bergers in lots of 1000 to 2000. Yes, I drop well over $1000 on bullets every yr, probably closer to $2000 than I'd admit.
With the exception of the Sierra 183 in .284 SIE don't make a single bullet in any class that can run BC's side by side with Berger and since they went to the TMK they are about equal in $$.
For the kind of loading you are talking about doing in a 308 class bullet I'd be loading the Sierra Game King 165 SPBT. I used to shoot them in a heavy barreled 308 that I mostly used for hunting before I built a 7-08. From a factory barrel, loaded over Varget in LC brass I had from shooting up some 147gr M80 ball, they'd shoot 3/4 MOA or better at 200 yards every time and they shot to almost the exact same zeros as the 168SMK loaded to the same velocity.
Give them a try.
Edit: another bullet that I have had good luck shooting that is/was a cost effective alternative to Bergers for me when I was shooting club matches in Oak Ridge was the 178 Horandy BTHP, but I'm not sure Hornady still makes that bullet. They used to run about $32 a box if I recall.
As for bullets for long range shooting. In F class competition I don't know of anyone who is not shooting Bergers. It's interesting that no other bullet company out there has stepped up to the plate to compete with them in the long range game. The only exception that I know of are a few Open guns that run the 183SMK (pointed not non-tipped) and in the PRS game some of the 6mm guys are running the 108SMK (again, pointed not tipped).
2nd edit: one other comment on Sierras. The 2156 Palma bullet is a great bullet, and when Applied Ballistics tested the 155TMK the BC came in at almost exactly the same as the BC for the [2156]