falconduke, all,
I cast another vote for H-4831. My load in all my 270s, save one, is 59.5 grains H-4831, WW brass, CCI primers, and any good 130 grain bullet. My one 270 that doesn't like this load is a custom Heym that apparently has a tighter than normal chamber as 59.5 grains flatten primers in that rifle. I've dropped it back to 58.0 grains for that rifle.
O'Connor did use and publicize the 62.0 grain load in his rifles. He used it and it worked for him. The problem with that load, other than the fact that it is hotter than hades, is that it's tough to get that much powder into a 270 case. O'C used a drop tube. That load was, as already reported, using the original surplus 4831. I suspect that 60 grains of the new stuff pretty much equates to 62 grains of the original. Anyway, it is really a compressed load.
Tom