XL5, I've used QL in conjunction with the OBT hypothesis. It has been distinctly un-useful to me in that application. The Optimal Charge Weight (OCW) development method has been _dramatically_ more efficient and effective for me.
I will acknowledge that QL was much closer when I used single-base extruded powders (i.e. the old Canadian IMR-4198 in metal cans). With the powders I normally use, however, there is more than one powder-cartridge-bullet combination with which there is NOTHING I can do to make the various numbers square. So, QL (and therefore OBT) remains an entertaining diversion that is not used by me for such practicalities.
