Happy news, 70 grains of FFg sitting on top of 10 grains of SR4759 is a formula equivalent to 100 grains of BP. No drop tube used. Layered into a Norma .458 WM case (which has a once-fired gross H2O capacity of about 99 grains) the powder level is about 0.4" from case mouth. Placing one of the poker-card wads over the powder, and simply running the RCBS neck expander/belling plug back into the case for proper belling depth, leaves the over-powder poker-card wad about 0.710" below the case mouth. Plenty of room for a BWOOB of lube with the 570-gr bullet seated to first cannelure/grease groove. All grease inside of case. COL of that cartridge will be about 3.34". Good in any SAAMI .458 WM if it will shoot accurately.
Paper-patched will be left long in the COL. They slip into the case with no neck expanding or belling needed other than a kiss from the plug to round the case mouths. Plenty of room for a lube BWOOB there. I don't guess it could hurt unless it makes the paper patch stick to the base of the bullet, so maybe a second poker-card wad to make a BWOOB sandwich between powder and bullet ? Maybe a double BWOOB if needed to fill the case for no powder shake.
I could put a single thickness paper "wad" (.002") between the SR4759 and the BP, but I guess not necessary with compressed BP for the 570-grain greaser, or 100% filled with BWOOB for the paper-patched 555-grainer, for no powder movement inside the case. F215 primer.
Ron aka "Rip" for Riflecrank Internationale Permanente NRA Life Benefactor and Beneficiary .458 Winchester Magnum, Magnanimous in Victory THE WALKING DEAD does so remind me of Democrap voters. Donkeypox.
