The Woodleigh Hydro solids hydrostatically stabilized are awesome for deep, straight line penetration on DG buff, elephant, etc.they're designed like modern Kynoch solids but with better stability.
The Woodleigh manual skimps on Hydro data because they're newer specialty, and most folks use standard solid soft data as a baseline same weight, adjust for profile if needed. Hydro solids are very similar ballistically to Woodleigh FMJ solids same weight, similar BC ~0.26–0.34, so published solid loads are safe starting points.
For .470 NE 500gr Hydro solid
IMR 3031: Many love it 78–80gr with Dacron filler 2gr is common for 2,150 fps Ken Owen PH favorite. Start 76gr, work up in 1gr steps.
RL 15: 84–88gr is reported e.g., 87gr for 2,150–2,200 fps in some doubles. Start 82–84gr, watch pressure.
Norma data for 500gr FMJ 84–86gr RL-15 equivalents, but cross check with your rifle.
For .416 Rigby 400gr Hydro solid
IMR 3031 Not common most use slower powders H4350 RL19 H4831 for 2,350–2,400 fps.
RL-15: 92–97gr e.g., 96gr H4350 equiv 2,350–2,400 fps. Start 90–92gr, work up.
Federal Norma data for 400gr solids 95–100gr slower powders, but RL-15 can work mid range.
Casual take Start 5–10% below published solid data e.g., 75gr MR 3031 for .470, 85gr RL-15 for .416, use magnum primers Fed 215M, no filler unless needed for position. Chrono every step, watch for pressure hard bolt lift, flattened primers. Hydro solids act like FMJ solids, so no big differences safe to use solid loads as base.
