Hello all...new to both the Forum and reloading. In a lot of RCBS loading dies that I bought, there is a set labeled "45-1.5. F.L." with a Group "L". The top of the decapping/sizing die says, "RCBS 45 X 1.5 F.L. SP. B". Can someone please enlighten me which cartridge this set is used for? Thanks in advance....sorry if it is just a stupid question.