Ages ago, when I began handloading, the standard recommendation was to start (approx) 10% BELOW STARTING LOAD. NOT 10% below MAX, you started BELOW the listed starting load. ALWAYS! (unless there was a specific warning not to such as may be found with certain slow powders).
Agree, starting below the book starting load seems a bit timid. Since most sources' starting load is an arbitrary 10% reduction, another 10% is 19% below maximum.
Most. Lyman has some very light starting loads, like
.45 LC 255 SWC
8.5 gr Unique MAXIMUM,
6.0 (-17%) to start. For a whopping 590 fps.
It's only timid if your bullet length and hardness match theirs. If your seating depth is greater or your alloy much harder, then it is prudent to drop the load some more. In most instances with longer bullets in the relatively long revolver cartridge cases, 5% additional reduction is plenty. In stubby pistol cases, 10% more may be prudent with much extra seating depth. But YMMV, so pay attention to your spidey sense tingles.
