Re: first time 308 shooter needs advise!!!
Your mileage may vary, and I can only relate what I went through and how I approached this issue. I chose .308 since it is a widely available round with tons of variations. Everyone has their pet loads, pet bullets, etc. And it was clear from reading many posts on the subject prior to my purchase, that I needed to look for a round that my rifle "liked".
After lots of reading, I focused on the 168 SMK. Most of my shooting is at 5900 ft. elevation, so this round can go out to 1K and beyond. However, since making that decision, I've learned more about it and once I run out of 168s I plan to go with 175s.
One of my goals was to aim for a "standard" ammo, maybe even try to match a hand load to a factory ammo so I would always know what to expect. I started by shooting a known good factory round (FGMM 168) so that I could rule out the ammo as a major source of variable. Just as I had read in the forums, this ammo is very good - very consistent.
Once I started working up hand loads in an attempt to match the FGMM, I began to realize it was no small task. For one thing, the powder they use is likely a non-cannister variant. Many people suggested that it was RL15, so that's what I used. Even with the minimum load recommended for this powder, I was still getting greater velocity than the FGMM. My goal then became to settle on the best grouping load of RL15 behind the 168s. I ended up with 40.2 grains, which is .2 grains above the min. recommended amount. It is still about 2" high at 200 yards vs. FGMM but it groups just as well (just had a .770" group at 200 yds a few weeks ago).
When I move to the 175s, I'll have to do another ladder test... good thing shooting is fun!