And when you DO start making those 308 loads, your approach is going to be superb! Maybe not in one tenth increments, but three tenths is perfectly reasonable for really narrowing it down to the most accurate load possible.
I also use 0.3 increments for accuracy testing in the .308 Win.
just some thoughts...
At longer ranges, looking at only one variables, amount of powder, you will see the results of multiple thing happening in the rifle...
1) The SD and ES of the MV. The ES alone at long range will determine the amount of vertical stringing (ignoring barrel harmonics, barrel heating, wind variance, and the shooter). This is why my chronograph is a more important precision reloading tool that the press itself, IMO. The SD will tell you what you might expect from the load when you load up 200 or so rounds for a match.
2) The effects of the load density. You can also see this in the ES and SD numbers. The lower the ES the smaller your groups will be.
3) The best ES and SD numbers might not shoot the smallest groups in your rifle, and this is where the dynamics of the rifle can come into play (mainly barrel harmonics, or in some cases a problem with the mounting or bedding in the stock). If the best ES and SD numbers don't coincide with the barrel harmonics (you want the bullet to exit the barrel at the peak of the vibration, when the barrel is motionless, not in between) then you start over with a different powder, or change the rifle in some way that changes the dynamics - but it's usually much simpler to try another powder, especially if you know that the bedding of the rifle is not the problem.
4) If you don't have a chronograph you can be chasing the wrong issue. Or end up saying, these bullets suck, of my gun doesn't like these bullets. Fact is, I haven't found a decent bullet, even cheap Sierras and Hornadys that won't go MOA (at 100 yards) or usually better with the right powder and load. Even with heavy barrels it can go from 1.5" to 0.5".
