For my .30-06, I was hoping to maximize performance with 195 TMK and 208 ELD-M. Accuracy wise, the .30-06 had a clear preference for H4831sc and H4350. With the 208s, H4350 and H4831sc were both around 2600 fps and SF yielded around 2675. To be fair, I never saw pressure with the SF, so it might have had more to give. I loaded up to 57.9 grains of SF. Shooting SF, that rifle was a 1 MOA gun. Shooting H4350 (52.9 grains) or H4831sc (58.8 grains), the same rifle was a 1/2 MOA gun.
Anyhow, long story longer, I've since parted ways with the .30-06 (for a song, too) and figured I might revisit the SF behind some 6.5 140s to grab a little performance back on the 20" tube. That was the impetus. I appreciate that Hodgdon lists 43.8 as book max @ 60.5 ksi for an astounding 2820 fps with a Swift A-frame. 2720 fps might be reasonable out of a 20" gun (and I'd certainly be happy with less), but only if it's consistent.
When I developed this load initially, it was doing 2680 fps out of a 22 inch barrel. I loaded from 43.2 grains to 45.2 grains for that final work-up. Settled on 44.2 grains because the two charge increments above showed inconsistent velocity/big ES. I had assumed that's because at/above max the progressive nature of the powder was causing erratic burn/pressure - could be a bad assessment on my part.
I shot it today out of a 20" Proof CF that seems close to my 22" based on some of the other ammo I chrono'd. That said, I clearly missed a trick somewhere. The SF loaded 140 ABs (old school, 1.405" length versus 1.368" for current) were at 2.8 COL. Definitely not in the lands, but the blunt shape of this bullet puts them about 30-40 thou off in a SAAMI cut chamber. My ES today was 151 on a 5 shot string that included an inadvertent pressure test load (which is why it was a five shot string). MV average was 2703 and the "hmm, time to stop now" shot came out at a blistering 2787 fps (LabRadar).
