This is the correct answer. The wrench that RCBS supplies with their Piggyback is about 6 inches long and is not very tough. Or hit up a local pawn shop. I lucked out and found one at a yard sale.Most my larger adjustable wrenches go to 1.5”
Find a HORNADY die lock ring...Any brand=any die, with a hex surface.
Screw the HORNADY die lock ring about mid-way down the die (Be sure the hex lock screw is completely loose and that the ring is spread as wide as possible), screw the die into your RCBS press and tighten down to the HORNADY lock ring tight with a wrench, then tighten up the hex lock screw. This will secure the die lock ring to the press hex nut.
Use whatever wrench on the ANY die to remove the entire assembly.
Other lock rings may?? work also, but I KNOW that the Hornady lock ring with a surface that you can tighten with a wrench (NOT pliers) will hold to the RCBS hex nut...
Had this happen by accident on my old RockChucker years ago...Bill.