Bob,

JB has actually addressed this before. I remembered reading his statements on it. Alliant was bidding to get RL-15 accepted as a military powder and the military wasn't happy with it's temp. sensitivity. So they went back and re-vamped it. Found it here:

https://www.24hourcampfire.com/ubbth..._Reloader_15_temp_sensitivit#Post3626654


“There are three things all wise men fear: the sea in storm, a night with no moon, and the anger of a gentle man.”
― Patrick Rothfuss, The Wise Man's Fear