Hadn't looked, but I know lots of manuals, Speer in particular, have revised their old load data down, as it was just too warm for some guns. It's one of those problems that come out of copper crushers being non-linear pressure indicators and sensitive to operator measuring skills. Old data run on them has proven unreliable in many instances, as the industry has changed over to piezo transducers. A lot of revisions have occurred as that changeover proceeds. A few up, but most down.
Some of Speer's data still is warm. There was a post at the Shooter's Forum not too long ago (can't recall the chambering or the powder) where the bottom load in the Speer #13 manual was higher than the max load for the same powder at Hodgdon's site. I think it was 41 Mag, maybe? I don't have #13 to check.
Once you have a single modern pressure system on the gun, if you see and apples-to-apples psi-to-psi comparisons, for example, where the Herco load is just plain lower in pressure, then I would suspect either that its bulk has filled the case or that some pressure sign showed up that isn't reflected by the pressure reading. Some powders have odd, peaky behavior under some conditions. That's why Blue Dot loads for the 125 grain .357 Mag loads and the .41 Mag got pulled by Alliant. They were getting occasional pressure spikes in their testing that they couldn't account for, and still can't, so they erred on the safe side.
