With large rifle primers in .308, I've researched, and found by experience, "softer" primers have much better SD numbers. By "softer" I mean the ignition or fire from the primers, not the cup hardness. Wolf and S&B primers where the best. Federal match primers are said to be real good, but I don't like the cup softness, nor the "touchiness" of these primers, especially when used for semi autos, like those with floating firing pins.
Also found an improvement with small primer .308 Lapua Palma brass, however, I needed to ream the flash hole larger (normal size) and use CCI 450 small magnum primers to ensure reliable ignition of the powder. The single digit SDs where similar to slightly better than that of the large primer wolf/S&B loads, but the better pressure handling and case longevity of the small primer brass made the decision to use .308 Palma brass for my target loads an easy one.