I've seen relevant load data for WSF poweder and 147gr lead ranging from Lyman (3.4gr - XXX @1.058" OAL) to Hodgdon (3.7 - 4.1gr @ 1.169" OAL). As it happens I've loaded at both OAL at the low end and had good results?
When a powder manufacturer tests a new powder, or in the case of WSF when Winchester many years ago tested WSF, do the test over a broad range of OAL/powder weight combinations mindful of chamber pressure? Or are they really just looking for one range at an OAL that "works" and use as a starting point results from a similar powder? 1.169" is on one end of the SAAMI spec and 1.058" seems pretty short. Of course bullet characteristics will enter into the results.
When a powder manufacturer tests a new powder, or in the case of WSF when Winchester many years ago tested WSF, do the test over a broad range of OAL/powder weight combinations mindful of chamber pressure? Or are they really just looking for one range at an OAL that "works" and use as a starting point results from a similar powder? 1.169" is on one end of the SAAMI spec and 1.058" seems pretty short. Of course bullet characteristics will enter into the results.